Side Effects, Dosage, Uses, and More

Highlights for dutasteride

1. Dutasteride oral capsule is available as a brand-name drug and a generic drug. Brand name: Avodart.
2. Dutasteride comes only as a capsule you take by mouth.
3. Dutasteride is used to treat benign prostatic hyperplasia (BPH), which is also called enlarged prostate. Dutasteride is only prescribed for men.

• Prostate cancer warning: Dutasteride may increase your risk of prostate cancer. Your doctor will check if you have prostate cancer by doing a blood test for prostate-specific antigen (PSA) before and during your treatment with dutasteride. Dutasteride lowers PSA concentrations in your blood. If there is an increase in your PSA, your doctor may decide to do more tests to check if you have prostate cancer.
• Pregnancy warning: If a woman is pregnant with a male baby and accidently gets dutasteride in her body by swallowing or touching dutasteride, the baby may be born with deformed sex organs. If your female partner becomes pregnant or is planning to become pregnant and her skin comes in contact with leaking dutasteride capsules, she should wash the area with soap and water immediately.
• Blood donation warning: Don’t donate blood for at least 6 months after stopping dutasteride. This helps prevent passing dutasteride to a pregnant woman receiving the blood.

Dutasteride is a prescription drug. It comes only as an oral capsule.

Dutasteride is available as the brand-name drug Avodart. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, the brand-name drug and the generic version may be available in different forms and strengths.

Dutasteride may be used as part of a combination therapy. That means you need to take it with other drugs.

Why it’s used

Dutasteride is used to treat benign prostatic hyperplasia (BPH), which is also called enlarged prostate.

When the prostate is enlarged, it can pinch or squeeze your urethra and make it harder for you to urinate. Dutasteride helps increase your urine flow and decrease your risk of a complete blockage of urine flow (acute urinary retention).

In some cases, these actions can reduce the need for prostate surgery.

How it works

Dutasteride belongs to a class of drugs called 5 alpha-reductase inhibitors. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

There’s a hormone in your blood called dihydrotestoterone (DHT) that causes your prostate to grow. Dutasteride prevents the formation of DHT in your body, causing an enlarged prostate to shrink.

Dutasteride oral capsule doesn’t cause drowsiness, but can cause other side effects.

More common side effects

The more common side effects that can occur with dutasteride include:

• trouble getting or keeping an erection
• decrease in sex drive
• ejaculation problems
• decrease in sperm count and activity

These effects may continue after you stop taking dutasteride.

Another common side effect is enlarged or painful breasts. This may go away within a few days or a couple of weeks. If it’s severe or doesn’t go away, or if you notice breast lumps or nipple discharge, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

• Allergic reactions. Symptoms can include:
  • swelling of your face, tongue, or throat
  • peeling skin
• Prostate cancer. Symptoms may include:
  • increased prostate-specific antigen (PSA) concentrations
  • increased urination frequency
  • trouble starting urination
  • weak urine flow
  • painful/burning urination
  • trouble getting or maintaining an erection
  • painful ejaculation
  • blood in your urine or semen
  • frequent pain or stiffness in your lower back, hips, or upper thighs

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

Dutasteride oral capsule can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with dutasteride are listed below.

HIV drugs

Taking dutasteride with drugs used to treat HIV called protease inhibitors can cause more dutasteride to stay in your blood. This can increase your risk of side effects.

Examples of these drugs include:

• atazanavir
• darunavir
• fosemprenavir
• indinavir
• lopinavir
• nelfinavir
• ritonavir
• saquinavir
• tipranavir

Fungal infection drugs

Taking dutasteride with certain drugs used to treat fungal infections can cause more dutasteride to stay in your blood. This can increase your risk of side effects.

Examples of these drugs include:

• itraconazole
• ketoconazole
• posaconazole
• voriconazole

Blood pressure drugs

Taking dutasteride with certain drugs used to treat high blood pressure can cause more dutasteride to stay in your blood. This can increase your risk of side effects.

Examples of these drugs include:

• verapamil
• diltiazem

Acid reflux drug

Taking cimetidine with dutasteride can cause more dutasteride to stay in your blood. This can increase your risk of side effects.

Antibiotic

Taking ciprofloxacin with dutasteride can cause more dutasteride to stay in your blood.

This can increase your risk of side effects.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

Dutasteride comes with several warnings.

Allergy warning

Dutasteride can cause a severe allergic reaction. Symptoms can include:

• rash
• swelling of your face, tongue, or throat
• trouble breathing
• serious skin reactions such as skin peeling

If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 911 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it or other 5 alpha-reductase inhibitors. Taking it again could be fatal (cause death).

Warnings for people with certain health conditions

For people with liver disease: Your body may not be able to process dutasteride correctly. This may cause more dutasteride to stay in your blood, which can increase your risk of side effects.

For pregnant women: Dutasteride is a pregnancy category X drug. Category X drugs should never be used during pregnancy.

If a woman is pregnant with a male baby and accidently gets dutasteride in her body by swallowing or touching dutasteride, the baby may be born with deformed sex organs.

If your female partner becomes pregnant or is planning to become pregnant and her skin comes in contact with leaking dutasteride capsules, she should wash the area with soap and water immediately.

For women who are breastfeeding: Dutasteride should never be used in breastfeeding women. It isn’t known if dutasteride passes through breast milk.

For children: Dutasteride shouldn’t be used in children. This drug has not been established as safe or effective in children.

This dosage information is for dutasteride oral capsule. All possible dosages and forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

• your age
• the condition being treated
• how severe your condition is
• other medical conditions you have
• how you react to the first dose

Forms and strengths

Generic: Dutasteride

• Form: oral capsule
• Strength: 0.5 mg

Brand: Avodart

• Form: oral capsule
• Strength: 0.5 mg

Dosage for benign prostatic hyperplasia (BPH)

Adult dosage taken alone and in combination with tamsulosin (ages 18 years and older)

• Typical dosage: One 0. 5-mg capsule per day.

Child dosage (ages 0–17 years)

Dosage for people younger than 18 years old hasn’t been established.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

Dutasteride is used for long-term treatment. It comes with serious risks if you don’t take it as prescribed.

If you stop taking the drug or don’t take it at all: If you don’t take or stop taking dutasteride, you may have increased symptoms such as difficulty starting to urinate, straining while trying to urinate, a weak urine flow, frequent urges to urinate, or more frequent need to wake up during the night to urinate.

If you miss doses or don’t take the drug on schedule: Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much: You could have dangerous levels of the drug in your body. What happens when you take too much dutasteride isn’t known. Since there is no antidote for dutasteride, your doctor will treat whatever symptoms you experience.

If you think you’ve taken too much of this drug, call your doctor or seek guidance from the American Association of Poison Control Centers at 800-222-1222 or through their online tool. But if your symptoms are severe, call 911 or go to the nearest emergency room right away.

What to do if you miss a dose: Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working: You should have less difficulty starting to urinate, urges to urinate that are less frequent, and less straining while trying to urinate.

Keep these considerations in mind if your doctor prescribes dutasteride for you.

General

• You can take this drug with or without food. Taking it with food may help to reduce upset stomach.
• Don’t crush, chew, or open dutasteride capsules. The contents of the capsule may irritate your lips, mouth, or throat. Swallow the capsule whole.

Storage

• Store dutasteride capsules at room temperature between 68°F and 77°F (20°C and 25°C).
• Keep it away from high temperature, because it may become deformed or discolored. Don’t use dutasteride if the capsule is deformed, discolored, or leaking.
• Keep this drug away from light.
• Don’t store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

• Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
• Don’t worry about airport X-ray machines. They won’t damage your medication.
• You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled container with you.
• Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

Dutasteride may increase your risk of prostate cancer. Before and during your treatment with dutasteride, your doctor will check if you have prostate cancer by doing a blood test for prostate-specific antigen (PSA) to see if there are any changes.

Dutasteride lowers PSA concentrations in your blood. If there is an increase in your PSA, your doctor may decide to do more tests to check if you have prostate cancer.

Availability

Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead to make sure your pharmacy carries it.

Prior authorization

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

Dutasteride (Avodart): What You Need To Know

What Is Dutasteride

What Is Dutasteride?

Dutasteride is a treatment for androgenetic alopecia, which is also known as pattern hair loss. It was originally used to treat enlarged prostates; specifically, a condition called benign prostatic hypertrophy (BPH). It was approved in the US to treat BPH in 2001. (1) In recent years, it has shown promise as a treatment for hair loss.

Dutasteride is not yet approved by the FDA as a hair loss treatment. It was approved as a treatment for androgenetic alopecia in 2009 in Korea and Japan. Dutasteride for both hair loss and BPH is typically taken orally as a 0.5 milligram dose. (2)

Dutasteride is also sold under the brand names Avodart or Duagen. (1,3) They’re essentially the same medicine — dutasteride is simply the generic name.

Dutasteride is also sold under the names Combodart and Duodart when combined with the drug tamsulosin in the same medication. Tamsulosin is an alpha-blocker also used to treat BPH. When combined, oral dutasteride-tamsulosin treats BPH with very positive results. (19) This combination has only been used to treat BPH and not hair loss.

What Is Dutasteride Used For?

Dutasteride was first used to treat benign prostatic hypertrophy (BPH), a condition causing prostate gland enlargement. It’s now approved as a hair loss treatment for androgenic alopecia in South Korea and Japan. (2)

Androgenic alopecia (pattern hair loss) affects up to 50 percent of men and women across the world. (4) Initial results show dutasteride could be effective in treating both male and female pattern hair loss. (5)

Although dutasteride for hair loss it isn’t yet approved in many countries, it’s widely used off-label with positive results. (6) Regardless of the form you choose to get dutasteride in, you should be aware that you’ll likely need a prescription from your doctor to obtain this medication.

How Much Does Dutasteride Cost?

Dutasteride varies in price depending on where you live and how you access your medication. In Japan, where dutasteride is approved to treat hair loss, prices average at JP¥11,500 for 30 pills. This is the equivalent of $104.52 USD ($3.40 per pill).

Dutasteride costs slightly less in most other countries. For example:

• In the US, dutasteride pills cost between $0.68 and $6.06 each.
• In the UK, prices range between £0.10 and £0.76.
• In Canada, prices range between CA$0.28 and CA$1.67 per pill.

Dutasteride is not yet approved as a hair loss treatment in these countries, but is still sometimes used off-label to treat androgenic alopecia.

How Does Dutasteride Work?

How Does Dutasteride Work?

Dutasteride is a dihydrotestosterone (DHT) blocker. It works by lowering levels of DHT, reducing the amount of DHT binding to the hair follicles. High levels of DHT is one of the primary causes of androgenic alopecia. (7)

DHT is a naturally occurring hormone derived from testosterone. However, in some people, it binds to hair follicles and progressively shrinks them, a process known as miniaturization. This shortens the hair growth cycle and causes thinner, weaker hair to grow. Over time, it can stop hair growth altogether. Hair follicle miniaturization can occur to both men and women. (8)

DHT is converted from testosterone by enzymes known as 5 alpha-reductase isoenzymes. There are three of these isoenzymes, which are simply called type 1, type 2, and type 3. Scientists think types 1 and 2 are the most significant for hair loss.

Dutasteride blocks all three types of isoenzymes indefinitely, stopping them from turning testosterone into DHT. (9) Research shows that a regular dose of 0.5 milligrams of dutasteride can reduce serum DHT levels by up to 92 percent and scalp DHT levels by up to 51 percent. (2) Lower levels of DHT in the body and scalp reduces the amount of DHT binding to hair follicles. This prevents further hair loss and gives healthy hair a chance to grow.

What Is a DHT Blocker?

DHT blockers work to reduce levels of dihydrotestosterone (DHT) in the body. DHT is a naturally occurring hormone present in both men and women. Testosterone, another hormone, is converted into DHT. DHT blockers stop this conversion process.

DHT is usually helpful, playing an essential role in male development. However, it binds excessively to some people’s hair follicles, causing them to shrink. In turn, this causes thinner, weaker hair and progressive hair loss. DHT blockers help to stop hair loss and allow hair to regrow over time.

There are two main DHT blockers used for hair loss: dutasteride and finasteride. Finasteride is FDA-approved. Dutasteride is only approved in Korea and Japan but is used off-label for hair loss in other countries. This medication is stronger and more effective than finasteride as it reduces DHT levels more significantly (7).

Finasteride and dutasteride are medications. However, that natural DHT blockers also exist. DHT blocking nutraceuticals are sometimes incorporated into supplements, shampoos, and. otherhair products.

Do Dutasteride and Finasteride Work in the Same Way?

Dutasteride and finasteride are the two main DHT blockers used to treat androgenetic alopecia. Both essentially work in the same way: by reducing levels of dihydrotestosterone (DHT) in the body to combat hair loss. However, there are small but very significant differences in their mechanism of action.

DHT is a hormone that is one of the main causes of androgenetic alopecia, the most common form of hair loss. (2) DHT is derived from testosterone, another vital hormone. In some people, DHT binds to their hair follicles, causing shrinkage and eventual hair loss.

Three 5-alpha reductase isoenzymes, known as type 1, 2, and 3, convert testosterone to DHT. Finasteride inhibits type 2 and 3, while dutasteride inhibits all three types. It’s important to mention that type 1 and 2 are thought to be the most important in preventing hair loss. Therefore, dutasteride is a more potent and effective DHT blocker. (9)

Dutasteride has a longer serum half-life than finasteride, which simply means it’s stronger and lasts in a patient’s system for longer. (10) Dutasteride binds to the isoenzymes irreversibly while finasteride doesn’t. This means dutasteride blocks their action indefinitely and, therefore, produces longer-lasting results. (10)

Dutasteride Effectiveness

Does Dutasteride Work?

Dutasteride is a highly effective dihydrotestosterone (DHT) blocker. It’s proven to have long-lasting results when treating androgenetic alopecia. (2)

DHT is a hormone that occurs naturally in the body and is usually useful. But in some people, DHT can bind to hair follicles, causing them to shrink. This leads to thinner hair and, eventually, can prevent hair growth, causing balding. DHT is one of the leading causes of androgenetic alopecia. This form of alopecia is one of the most common forms of hair loss and can be very distressing for those experiencing it. (2)

Dutasteride works by reducing levels of DHT to help reduce the chance of this binding process. This gives healthy hair a chance to grow and prevents further hair loss. Research shows that a dose of 0.5 milligrams per day of dutasteride can reduce DHT levels in the bloodstream by as much as 92 percent, and levels of DHT in the scalp by up to 52 percent. (2)

Recent studies show dutasteride is a promising treatment for female-pattern hair loss (the type of androgenic alopecia affecting women). A 2019 study showed a significant increase in both crown and temple hair density in women taking a low dose of dutasteride. (5) It also shows promise in treating frontal fibrosing alopecia (FFA), a form of hair loss primarily seen in postmenopausal women. (11)

How Long Does It Take Dutasteride to Work?

When taking a daily dutasteride dosage of 0.5 milligrams, patients typically start to see positive results such as a reduction of hair loss after an average of 3 months. After 6 months, patients usually notice significant changes to their hair, including increased hair growth and hair thickness. (12)

Dutasteride is a dihydrotestosterone (DHT) blocker that stops further hair loss, allowing healthy hair to grow. It’s important to remember that this is a long-term treatment, so patience and consistency are needed to see results.

How Effective Is Dutasteride?

Dutasteride is a very effective treatment for androgenetic alopecia. Patients taking dutasteride see significant, long-lasting prevention of further hair loss and promotion of healthy hair regrowth within 6 months. (12)

Dutasteride works as a DHT (dihydrotestosterone) blocker, lowering DHT levels in the body. DHT is a naturally occurring hormone made from testosterone. It’s one of the main causes of androgenetic alopecia. When DHT binds to the hair follicles, it causes thinner hair and hair loss. Dutasteride helps stop this process from occurring.

Three 5-alpha reductase isoenzymes work to convert testosterone to DHT. Dutasteride blocks all three isoenzymes, compared to finasteride which only blocks two out of the three. Dutasteride has a longer half-life than finasteride and binds to the isoenzymes irreversibly. This means dutasteride results are long-term, and the drug is more effective overall. (9)

A randomized controlled study found that men taking 0.5 milligrams of dutasteride per day over 24 weeks saw an impressive increase in hair growth and prevention of disease progression. Total hair count was increased by 23 cm², while thin hair count was decreased by 8 cm² .(12)

How Effective Is Topical Dutasteride?

Dutasteride is usually taken orally in daily 0.5 milligram doses. It’s not usually incorporated into topical products, like shampoos or hair oils, unlike many other hair loss treatments. However, it shows promise as a topical treatment. Topical dutasteride treatments have the potential to prevent hair loss and stimulate hair growth more than oral equivalents. (13)

Topical dutasteride is sometimes combined with other topical hair loss treatments, like finasteride and minoxidil. A pilot study of a lotion combining all three of these topical ingredients saw very positive results. Although the patient group was small, with only 15 participants, all patients saw a significant increase in hair growth. (14)

Dutasteride mesotherapy is another method of topical application. It involves applying micro-injections of dutasteride directly onto the scalp. Mesotherapy is minimally invasive, and while it isn’t yet widely studied, initial research shows it could be very effective. During mesotherapy, a combination of ingredients is typically used. For example, in one study, a preparation of dutasteride 5 milligrams, D-panthenol 500 milligrams, biotin 20 milligrams, and pyridoxine 200 milligrams was used. This combination increased hair diameter and thickness and reduced hair loss. Mesotherapy will typically be administered once every week to 10 days for a number of weeks to see results. (8)

In some studies, dutasteride was also injected alongside ingredients like biotin and vitamin B6. A trichogram analysis, which is a microscopic examination of hairs plucked from the scalp, was used to examine hairs following this treatment. When looked at under the microscope, researchers saw healthier hair strands. This showed that the results were even more effective than using dutasteride alone. (8)

Since topical dutasteride is applied directly to the scalp, it’s less likely to cause systemic side effects. However, mesotherapy treatments have their own side effects, such as scalp irritation and, paradoxically, hair loss in some cases. (8)

Dutasteride Side Effects

Does Dutasteride Have Side Effects?

Like any medication, dutasteride has potential side effects. The majority of side effects are related to sexual function. These sexual side effects may include a decreased libido, issues with ejaculation, and impotence. It can also cause gynecomastia, the enlargement of breast tissue, in some people. However, research shows that these side effects occur in less than 1 percent of patients. In general, dutasteride is well tolerated and safe for use. (19)

Dutasteride can affect the liver, as androgens play an important part in liver function. Other dutasteride side effects include swelling, depression, skin irritations, and fatigue. However, these side effects typically occur in less than 1 percent of patients. (19,20)

It’s important to remember that all medications have potential side effects. Being aware of them can help you to make an informed choice.

Does Dutasteride Have Sexual Side Effects?

Dutasteride has several potential sexual side effects. These include a reduced sex drive, ejaculation disorders, impotence, and enlargement of the breast tissue (gynecomastia). While these side effects can be distressing for patients, research suggests they only occur in as few as 1 percent of people taking 0.5 milligrams of dutasteride. (19)

Dutasteride is a dihydrotestosterone (DHT) blocker. It works to block excess levels of DHT from binding to the hair follicles. Oral dutasteride works systemically and affects androgens, known as male sex hormones. Therefore, in some people, it can result in sexual side effects.

It’s important to know the risks before taking any medication so that you can make the best choice for your health. A review of research on the topic found that over 2 years, the incidence of sexual side effects was only slightly higher in dutasteride-treated patients than among placebo-treated patients. (19) Interestingly, sexual side effects seem to decrease the longer the patient takes dutasteride. (2) Overall, dutasteride is thought to be a safe and highly effective hair loss treatment.

Will Dutasteride Cause the Same Side Effects as Finasteride?

Dutasteride and finasteride are the two primary dihydrotestosterone (DHT) blockers used to treat androgenetic alopecia. Dutasteride causes very similar side effects as finasteride as they both work in very similar ways. (21)

DHT is a hormone that can bind to the hair follicles, causing hair thinning and hair loss. DHT blockers work to stop this process and allow healthy hair to grow. Since DHT blockers work systemically on androgens (‘sex’ hormones), they can have adverse sexual effects.

Finasteride and dutasteride both cause sexual side effects, including lowered libido, erectile dysfunction, and problems with ejaculation. These medications typically cause similar amounts of side effects. A 2019 systematic review found no significant differences in the rates of side effects in patients taking finasteride or dutasteride for 24 weeks. (21)

Post-Finasteride Syndrome (PFS) is a condition affecting men who have taken finasteride, dutasteride, or other DHT blocking medications. Symptoms include adverse sexual, mental, and physical effects. (22)

PFS is a controversial topic, as most medical community members don’t recognize it as a ‘real’ syndrome. However, it’s very real for those experiencing it. More recent research emphasizes the need for this collection of side effects to be taken seriously to aid existing patients and better inform potential patients. (23)

Can Dutasteride Cause Prostate Cancer?

Dutasteride is a dihydrotestosterone (DHT) blocker used to treat benign prostatic hypertrophy and androgenic alopecia. Original research found that dutasteride and finasteride (another DHT blocker), can lower the risk of prostate cancer. However, they may slightly increase the risk of high-grade prostate tumors. (24)

Due to these findings, a warning is often present on the prescribing information that comes with these pills. However, more recent research suggests that there isn’t an increased risk of prostate cancer in those taking DHT blockers.

A meta-analysis on the topic found that there was up to a 37 percent decrease in the risk of prostate cancer in those taking dutasteride. There was also no significant increased risk of high-grade tumors. (24)

This misconception exists because dutasteride can mask the growth of tumours, leading to later detection. The issue isn’t that dutasteride is causing the tumor or cancer, but that taking this medication might prevent it from being detected until it has already spread.

Does Dutasteride Have Any Drug Interactions?

Dutasteride does have some potential drug interactions. A cancer treatment drug called ceritinib and an antibiotic called clarithromycin can both interact with dutasteride.

A range of other dutasteride interactions are possible, including with ketoconazole, which can also be used to treat androgenetic alopecia. (25) While this combination is generally safe, it may increase the risk of side effects. Make sure to check with your doctor about any drug interactions before beginning dutasteride treatment to ensure your safety.

Dutasteride Alternatives

Finasteride vs. Dutasteride

Both finasteride and dutasteride are dihydrotestosterone (DHT) blockers. They were initially used to treat enlargement of the prostate gland, known as benign prostatic hypertrophy. They later became hair loss treatments. Both finasteride and dutasteride are usually taken orally, although they are also available topically.

Finasteride and dutasteride work to reduce levels of DHT, therefore reducing the amount of DHT binding to the hair follicles, one of the main causes of androgenetic alopecia. Although they work in very similar ways, there are slight differences in their mechanism of action. Essentially, dutasteride is more potent and more effective than finasteride. (21)

Since dutasteride is more potent, it’s taken in smaller doses. Dutasteride is usually taken in 0.5 milligram daily doses. (2) Finasteride pills are typically taken in 1 milligram daily doses for hair loss.

Finasteride is approved by the US Food and Drug Administration (FDA) and other equivalent health boards for the treatment of androgenetic alopecia. Dutasteride is not yet approved by the FDA for hair loss. It’s currently only approved in South Korea and Japan. However, it has gone through many clinical trials in other countries, including Argentina, Australia, and America. (26) It’s also used off-label in countries where it is not yet approved as a hair loss treatment.

Both finasteride and dutasteride have similar potential side effects, including adverse sexual side effects. In general, both drugs are well tolerated, and research suggests they’re safe for use. (21)

Dutasteride often costs a similar amount to finasteride when used to treat hair loss. Many studies concluded that both DHT blockers cost around the same price per month in the USA. (27) How you access dutasteride and where you live will also have a significant impact on cost.

What Is the Difference Between Finasteride and Dutasteride?

Dutasteride and finasteride work in very similar ways, but there are slight differences in how they work. These differences make dutasteride more potent and, therefore, more effective at lower doses. (21)

Dutasteride and finasteride are both dihydrotestosterone (DHT) blockers. They both work to reduce levels of DHT. They do this by inhibiting the conversion of testosterone to DHT. This lowers levels of DHT in the bloodstream and reduces the amount of DHT binding to the hair follicles. DHT binding to the hair follicles is one of the main causes of androgenetic alopecia.

DHT is a hormone made from testosterone. Isoenzymes are chemicals that work to convert testosterone into DHT. Three isoenzymes play a part in this process. They’re known as 5-alpha reductase isoenzymes types 1, 2, and 3. Type 1 and 2 are understood to be the most important for hair loss. (8)

Finasteride inhibits the action of types 2 and 3 of these isoenzymes. Dutasteride inhibits all three types. It can be up to three times more potent at inhibiting the type 2 enzyme than finasteride. (14)

Dutasteride also binds to the isoenzymes irreversibly while finasteride does not. This means dutasteride continues to inhibit the action of the isoenzymes in the long term, producing long-lasting results. (10)

Oral dutasteride decreases DHT serum levels by up to 90 percent. In contrast, finasteride only reduces levels by up to 70 percent. Fundamentally, these differences mean that dutasteride is more effective at reducing DHT levels than finasteride. (8)

Can You Switch From Finasteride to Dutasteride?

Finasteride and dutasteride are dihydrotestosterone (DHT) blockers used as treatments for androgenetic alopecia. However, dutasteride is more potent than finasteride due to a slight difference in how it works. Some people choose to switch from finasteride to dutasteride because of this. (14)

Switching to dutasteride is generally considered safe. It’s also shown to be effective, especially for patients who weren’t showing clinical improvement while taking finasteride. But since finasteride is a long-term treatment, patients should try finasteride for at least 6 months before considering a new medication. (28)

If you intend to switch medications, be aware that it can take another 3 to 6 months before you see results from dutasteride. One study found that after switching to a 0.5 milligram dose of dutasteride for six months, patients experienced a significant improvement in hair density and thickness. (28)

Since dutasteride is a more potent DHT blocker, in some patients it can result in a higher incidence of sexual dysfunction. Therefore, it’s crucial patients are well informed before making the change.

If patients experience more side effects with dutasteride, they can switch from dutasteride to finasteride. For some, finasteride may be more suitable, particularly as this drug is FDA-approved. However, this switch may cause some hair shedding and less hair density over time. (29)

Are There Any Other DHT Blocking Alternatives to Dutasteride?

Dutasteride and finasteride are the primary dihydrotestosterone (DHT) blockers used to treat hair loss. Natural DHT blockers are also available, such as the popular nutraceutical saw palmetto. Saw palmetto is an extract that comes from the berries of a type of palm tree. Other nutraceutical DHT blockers include stinging nettle, pumpkin seed oil, lycopene, tea tree oil, and caffeine.

Natural DHT blockers are often incorporated into topical treatments such as shampoos, hair oils, and sprays. But research shows these alternatives aren’t as effective as dutasteride or even finasteride since they don’t lower DHT levels as much. (30)

Dutasteride Combination Treatments

Can You Combine Dutasteride With Any Other Treatments?

Dutasteride can be combined with other hair loss treatments. In some cases, these combinations may be more effective than dutasteride alone. (15) It’s important to remember that these combinations are not approved by the FDA or any other relevant authority. Consult your doctor before starting any combination treatment, as combining medications and even nutraceuticals may not always be safe.

Dutasteride and finasteride are the two main dihydrotestosterone (DHT) blockers used to treat androgenetic alopecia. The FDA has not yet approved dutasteride for use as a hair loss treatment, although finasteride is. Research shows that combining finasteride and dutasteride is safe and could be more effective than either treatment used on its own. One study of a 47-year-old man over a period of four years found that when 0.5 milligrams of dutasteride was added to his finasteride treatment, hair density increased significantly. (15)

Minoxidil is a hair loss treatment known as a vasodilator. It increases blood flow to the scalp, which widens the blood vessels and hair follicles. This allows thicker hair to grow. Minoxidil can be combined with oral or topical dutasteride. Research shows it could be an effective combination, with one study showing a total hair increase of 45.9 hairs per cm² .(17)

Ketoconazole is an antifungal medication that also acts as a DHT blocker. It binds to DHT receptors on hair follicles, preventing DHT from affecting them. It’s usually found in shampoos. Topical ketoconazole can be combined with topical dutasteride, and initial studies are promising as they seem to show that the combination could increase hair density and reduce hair loss. (14)

Patients may combine dutasteride with natural DHT blockers, such as saw palmetto, to try to improve their outcomes. Natural options may be taken as supplements or used topically while taking oral dutasteride. (30) It’s important to note these natural combinations are not well researched or proven to be safe.

Does Dutasteride Work Better When Combined With Other Treatments?

Dutasteride can be more effective when combined with other treatments. However, most of these combinations aren’t officially approved as safe. It’s important to do your research and consult your doctor before starting any combination treatment.

Dutasteride is a dihydrotestosterone (DHT) blocker. DHT binding to the hair follicles is one of the leading causes of androgenetic alopecia. Dutasteride is sometimes combined with finasteride, another primary DHT blocker. When the two are used simultaneously, research suggests they may be more effective than either DHT blocker taken alone. (15)

Minoxidil, an FDA-approved topical treatment, is also sometimes combined with oral or topical dutasteride. (14) Minoxidil is a vasodilator, which increases blood flow to the scalp and widens blood vessels. This increases the size of the hair follicles, allowing healthier, thicker hair to grow. (16) Minoxidil combined with oral or topical dutasteride shows promise as a hair loss treatment, with the potential to increase hair growth and hair thickness. (17)

Ketoconazole is an antifungal medication, often seen in topical treatments like shampoos. It has anti-androgenic properties and also works as a DHT blocker. It’s a receptor antagonist, which means it binds to DHT receptors, blocking DHT’s action.

Ketoconazole has been studied since 1992. Although new studies are limited, results suggest that a shampoo containing 2 percent ketoconazole is highly effective in treating hair loss. (18) Initial studies show ketoconazole shampoo could be effective when combined with dutasteride. (14)

About the safety of Avodart (dutasteride) in patients with benign prostatic hyperplasia (BPH) | Alyaev Yu.G., Lokshin K.L.

5a-reductase inhibitors – a group of drugs used in clinical practice since the early 90s of the XX century. The very first drug of this group is finasteride.

After a number of preclinical and clinical trials [1], the drug was approved in the USA for wide clinical use in patients with prostatic hyperplasia in 1992, and then, in 1995, was registered in Russia. Somewhat later, finasteride was developed potentially more powerful inhibitor of 5a-reductase I and type II – dutasteride: the results of the first clinical trials of this drug appeared in the literature in 1998 [2]. Unlike finasteride, dutasteride has the ability to inhibit not only 5a-reductase II, but also type I [3] – thus, the drug provides maximum suppression of dihydrotestosterone production. In Western countries, dutasteride under the commercial name “Avodart” was registered and approved for clinical use in 2002, in Russia – in 2005.
It is well known that both before and after official registration, medicines are tested not only for their effectiveness, but also for safety. The effectiveness of the use of 5a-reductase inhibitors in patients with BPH has always received much attention, and this problem is well covered in the medical literature. In this article, we would like to focus on the results of recently completed large clinical trials that examined the safety and tolerability of Avodart (dutasteride) therapy.
Comprehensive data on the safety and tolerability of Avodart (dutasteride) in patients with BPH have been obtained in three large, randomized, double-blind, placebo-controlled trials (ARIA 3001, ARIA 3002, and ARIB 3003 [4]) and one randomized, double-blind trial (ARI 40001, [5]), in which patients in the control group received finasteride. The ARIA 3001, ARIA 3002 and ARIB 3003 studies included 4325 patients with BPH (2167 in the dutasteride group, 2158 in the placebo group), the duration of therapy was 2 years. A total of 1630 patients were randomized to a finasteride-controlled study with a duration of treatment of 1 year: 813 to dutasteride and 817 to finasteride. Note that the number of patients in the groups and the duration of therapy are more than sufficient to evaluate the efficacy and safety of the study drug.
An analysis of the data obtained in the course of the placebo-controlled studies mentioned above showed that the adverse events (AEs) that occurred were usually mild or moderate in severity and most often related to disorders of sexual function (Table 1). At the same time, both in the Avodart group and in the placebo group, the vast majority of patients (89% and 94%, respectively) had no sexual dysfunction.
Interestingly, in terms of the frequency of reported drug-related adverse events, statistically significant differences between the dutasteride and placebo groups, as a rule, were observed only during the first 6 months of therapy. In the course of further treatment, the differences between the groups in the most common adverse events disappeared. So, for example, in the first 6 months of treatment, erectile dysfunction (ED) was observed in 4.7% of patients in the dutasteride group and in 1.7% of patients in the placebo group – the differences between the groups were statistically significant. Subsequently, the frequency of ED in the groups had no significant differences, amounting to 7–12 months of 1.4% and 1.5%; at 13–18 months – 1% and 0.5%, and at 19-24th month – 0.8 and 0.9%, respectively. A similar pattern was found for somewhat less common ejaculation disorders and decreased libido. Gynecomastia was the only adverse event associated with taking the drug and significantly more common in patients in the dutasteride group, starting from the 7th month of admission and until the end of the study. The incidence of gynecomastia in the dutasteride group, however, was generally low and did not exceed 1.1% throughout the study. It is also important that among the adverse events, the most common reason for discontinuation of the drug was erectile dysfunction: in the dutasteride group there were 24 (1.1%) such patients, and in the placebo group – 15 (0.69%). Based on the presented data, it can be argued that long-term (over 2 years) dutasteride therapy is well tolerated, and only a small percentage of patients may experience clinically significant adverse events during this treatment.
A similar adverse event profile was reported in the finasteride-controlled study ARI 40001. Data from this study suggest that dutasteride and finasteride can cause similar adverse events (Table 2), the frequency and severity of the most significant of them are low, and the tolerability of both medicines are generally good.
It should be noted that in all the above studies, dynamic monitoring of a number of hematological (leukocytes, platelets, erythrocytes, hemoglobin, etc.) and biochemical (glucose, sodium, potassium, albumin, total protein, creatinine) laboratory parameters was also carried out, including indicators of liver function – alkaline phosphatase, ALT and total bilirubin. Analysis of the obtained results showed that taking dutasteride does not adversely affect any of the studied laboratory parameters. Changes in parameters in the dutasteride group did not differ from those in the placebo group and in the finasteride group.
The safety of Avodart (dutasteride) in humans has also been studied in healthy volunteers. Thus, in connection with the theoretical possibility of drugs that modulate testosterone metabolism to affect bone density, a randomized, double-blind, placebo- and finasteride-controlled study (ARIA 1009) was conducted, which evaluated the effect of dutasteride on bone density (by X-ray densitometry), indicators bone metabolism (osteocalcin, serum alkaline phosphatase and urine n-telopeptide), as well as lipid profile (cholesterol, triglycerides, high and low density lipoproteins of blood serum) [5]. The duration of therapy was almost 1 year (52 weeks) with follow-up examinations for 24 weeks. The results of the study showed no signs of a negative effect of dutasteride on bone metabolism and human lipid profile. The data obtained in the dutasteride group did not differ from those in the placebo and finasteride groups.
Also, drug interactions of dutasteride with drugs most often used in elderly patients are currently well studied. Thus, there were no pharmacodynamic and pharmacokinetic interactions between dutasteride and tamsulosin (data from the ARIA1011 study), warfarin (data from the ARI10016 study), digoxin (data from the ARI10017 study) and cholestyramine (data from the ARIA1010 study). In subsequent phase 3 studies, no clinically significant interactions of dutasteride with ACE inhibitors, b-blockers, calcium channel antagonists, diuretics, corticosteroids, antihyperlipidemic agents, non-steroidal anti-inflammatory drugs, fluoroquinolones, and type 5 phosphodiesterase inhibitors were proven.
Thus, the results of studies conducted with the participation of several hundred healthy volunteers and more than 6,000 patients with prostatic hyperplasia allow us to state with confidence that even with prolonged use of the 5a-reductase inhibitor of both types Avodart (dutasteride), the drug is well tolerated, and its administration is associated with minimal the risk of adverse events.

Literature
1. Gormley GJ, Stoner E, Bruskewitz RC, et al. The effect of finasteride in men with benign prostatic hyperplasia. The Finasteride Study Group. N Engl J Med. 1992;327:1185–1191.
2. Gisleskog PO, Herman D, Hammarlund–Udenaes M, et al. A model of the turnover of dihydrotestosterone in the presence of the irreversible 5(–reductase inhibitors GI198745 and finasteride. Clin Pharmacol Ther. 1998; 64:636–647.
3. Bramson HN, Hermann D, Batchelor KW, et al. Unique preclinical characteristics of GG745, a potent dual inhibitor of 5AR. J Pharmacol Exp Ther. 1997;282:1496–1502.
4 Debruyne F, Barkin J, van Erps P, et al. ARIA3001, ARIA3002, ARIB3001 study investigators. Efficacy and safety of along term treatment with the dual 5–(–reductase inhibitor dutasteride in men with symptomatic benign prostatic hyperplasia. Eur Urol. 2004, 46:488–494.
5. GlaxoSmithKline Document BP2001/00017/00. Data on File. Clinical trial report study ARI 40001.

Avodart: instruction, price, analogues | soft gelatin capsules GlaxoSmithKline

• Pharmacological properties
• Indications Avodart
• Application Avodart
• Contraindications
• Side effects
• Special instructions
• Interactions
• Overdose
• Storage conditions
• Diagnosis
• Recommended alternatives
• Trade names

pharmacodynamics . Dutasteride is a dual 5α-reductase inhibitor that inhibits both type 1 and type 2 5α-reductase isoenzymes responsible for the conversion of testosterone to 5α-dihydrotestosterone. Dihydrotestosterone is an androgen that is primarily responsible for hyperplasia of prostate tissue. The maximum decrease in the level of dihydrotestosterone while taking Avodart depends on the dose and is noted in the first 1-2 weeks. After the 1st and 2nd weeks of using Avodart at a daily dose of 0.5 mg, the average concentration of dihydrotestosterone decreases by 85 and 90% respectively.

In patients with benign prostatic hyperplasia who received dutasteride 0.5 mg per day, the average decrease in dihydrotestosterone levels was 94% after 1 year and 93% after 2 years of treatment, the average testosterone level increased by 19% after 1 and 2 years .

Pharmacokinetics . Dutasteride is administered orally in the form of a solution in soft gelatin capsules. After taking a single dose of 0. 5 mg C _max of the drug in blood plasma is achieved after 1-3 hours. Absolute bioavailability is 60% when applied by 2-hour IV infusion. Bioavailability does not depend on food intake.

Single or multiple dose dutasteride has a large volume of distribution (300-500 L). The percentage of protein binding is more than 99.5%.

When used in a daily dose of 0.5 mg, 65% of the constant steady-state concentration of dutasteride in blood plasma is achieved after 1 month of treatment and about 90% after 3 months. A stable constant concentration of dutasteride of about 40 ng / ml in blood plasma is achieved after 6 months of treatment at a daily dose of 0.5 mg. As in blood plasma, a steady concentration of dutasteride in seminal fluid is reached after 6 months. After 52 weeks of treatment, the average concentration of dutasteride in seminal fluid is 3.4 ng / ml (within 0.4-14 ng / ml). The percentage of distribution of dutasteride from blood plasma to seminal fluid is about 11. 5%.

In vitro dutasteride is metabolized by human cytochrome P450 CYP 3A4 enzymes to two monohydroxyl metabolites.

Human plasma spectrometry shows unchanged dutasteride, 3 major metabolites (4′-hydroxydutasteride, 1,2-dihydrodutasteride and 6-hydroxydutasteride) and 2 minor metabolites (6,4′-dihydroxydutasteride and 15-hydroxydutasteride).

Dutasteride is extensively metabolized. Following oral administration of dutasteride at a dose of 0.5 mg/day, 1–15.4% (mean 5.4%) of the dose taken is excreted in the feces as unchanged dutasteride. The rest of the applied dose is excreted as metabolites.

Only traces of unchanged dutasteride (<0.1% of the administered dose) are detected in the urine. The final T _½ dutasteride is 3-5 weeks. Residues of dutasteride in blood plasma can be detected 4-6 months after the end of treatment.

Based on the study of pharmacokinetics and pharmacodynamics, it is not required to change the dose of dutasteride in accordance with the age of the patient.

The effect of renal failure on the pharmacokinetics of dutasteride has not been studied. However, when taking 0.5 mg of dutasteride, less than 0.1% of the dose is excreted in the urine in humans, so dose adjustment is not required for patients with renal insufficiency.

The effect of hepatic insufficiency on the pharmacokinetics of dutasteride has not been studied (see USE and SPECIAL INSTRUCTIONS).

Safety and clinical studies

Heart failure . In a 4-year clinical study of the use of dutasteride in combination with tamsulosin for the treatment of benign prostatic hyperplasia in 4844 men (CombAT study), the incidence of heart failure (collective concept) in the combination therapy group (14/1610; 0.9%) was higher than in any monotherapy group with dutasteride (4/1623; 0.2%) or tamsulosin (10/1611; 0.6%).

In a separate 4-year clinical trial comparing placebo with dutasteride chemoprevention in 8231 men aged 50 to 75 years with pre-negative biopsy results for prostate cancer and a baseline prostate-specific antigen (PSA) level of 2. 5-10.0 ng /ml in men aged 50–60 years or 3.0–10.0 ng/ml in men aged 60 years and over (REDUCE studies) it was found that the incidence of heart failure in patients who took dutasteride 0.5 mg once a day (30/4105; 0.7%), higher than placebo patients (16/4126; 0.4%). A retrospective analysis of this study showed a higher incidence of heart failure in patients treated with dutasteride and an α-adrenergic blocker simultaneously (12/1152; 1.0%) compared with subjects treated with dutasteride without an α-adrenergic receptor blocker (18/2953; 0.6%), placebo and α-blocker (1/1399; <0.1%), or placebo without α-blocker (15/2727; 0.6%). A causal relationship between the use of dutasteride (alone or in combination with α-adrenergic blockers) and the occurrence of heart failure has not been established (see SPECIAL INSTRUCTIONS).

Prostate cancer and poorly differentiated tumors . In a 4-year comparison study of placebo and dutasteride in 8231 men aged 50 to 75 years with a preliminary negative biopsy for prostate cancer and a baseline PSA level of 2. 5–10.0 ng/mL in men aged 50–60 years or 3.0–10.0 ng/ml in men aged 60 years and older (REDUCE studies) 6706 subjects underwent prostate needle biopsy (mandatory under the primary protocol), the data of which were used to analyze Gleason differentiation. The study identified 1517 patients diagnosed with prostate cancer. The majority of prostate tumors (70%) identified by biopsy in both treatment groups had a high level of differentiation (5–6 points on the Gleason scale).

A higher incidence (n=29; 0.9%) of poorly differentiated prostate cancer (8-10 points on the Gleason scale) was registered in the dutasteride group compared to the placebo group (n=19; 0.6%) (p= 0.15). In years 1–2 of the study, the number of patients with prostate cancer with a Gleason score of 8–10 was the same in the dutasteride group (n=17; 0.5%) and in the placebo group (n=18; 0.5 %). In the 3rd-4th years of the study, more cases of prostate cancer with a differentiation of 8-10 points on the Gleason scale were diagnosed in the dutasteride group (n=12; 0. 5%) compared to the placebo group (n=1; <0, 1%) (p=0.0035). There are no data on the effect on the risk of developing prostate cancer in men taking dutasteride for more than 4 years. The percentage of patients diagnosed with prostate cancer with a Gleason score of 8–10 remained constant at different study periods (1–2 years, 3–4 years) in the dutasteride group (0.5% in each period), while in the placebo group, the percentage of patients with low-grade prostate cancer (8–10 points on the Gleason scale) was lower in years 3–4 than in years 1–2 (<0.1 and 0.5 % respectively) (see SPECIAL INSTRUCTIONS). There was no difference in the incidence of prostate cancer with a Gleason score of 7–10 (p=0.81).

In a 4-year clinical study of the treatment of benign prostatic hyperplasia (CombAT), where the primary protocol did not provide for a mandatory biopsy, and all diagnoses of prostate cancer were established on the basis of a biopsy according to indications, the incidence of prostate cancer with a differentiation of 8–10 points according to The Gleason score was 0. 5% (n=8) in the dutasteride group, 0.7% (n=11) in the tamsulosin group, and 0.3% (n=5) in the combination therapy group.

The relationship between the use of dutasteride and the occurrence of poorly differentiated prostate cancer remains unclear.

Male breast cancer . Two controlled epidemiological studies, one in the US (339 breast cancers and 6780 controls) and one in the UK (398 breast cancers and 3930 controls), showed no increased risk of developing cancer breast cancer in men when using 5α-reductase inhibitors. The results of the first study did not reveal an association with breast cancer (relative risk (HR) when using ≥1 year before the diagnosis of breast cancer compared with using <1 year: 0.70: 95% confidence interval (CI) 0.34–1.45). In the second study, the relative risk of developing breast cancer associated with the use of 5α-reductase inhibitors compared with no use was 1.08: 95% CI 0.62-1.87).

A causal relationship between cases of breast cancer in men and long-term use of dutasteride has not been established.

treatment of symptoms of moderate to severe benign prostatic hyperplasia; reducing the risk of acute urinary retention and, if necessary, surgical intervention in patients with symptoms of moderate and severe benign prostatic hyperplasia.

Avodart can be administered alone or in combination with the α-adrenergic blocker tamsulosin (0.4 mg).

Adult males (including elderly patients) . The recommended dose of Avodart is 1 capsule (0.5 mg) per day for oral administration. The capsule should be swallowed whole, without opening or chewing, since contact with the contents of the capsule may irritate the mucous membranes of the mouth and pharynx.

Avodart can be taken with or without food.

Despite the fact that relief from taking the drug is noted at an early stage, for an objective assessment of the effectiveness of the drug, treatment should be continued for at least 6 months.

Renal failure . The pharmacokinetics of dutasteride in patients with renal insufficiency has not been studied, therefore, the drug should be administered with caution to patients with severe renal insufficiency.

Liver failure . The pharmacokinetics of dutasteride in patients with hepatic insufficiency has not been studied, therefore, the drug should be used with caution in mild and moderate hepatic insufficiency. Dutasteride is contraindicated in patients with severe hepatic impairment.

Children . Application is contraindicated.

hypersensitivity to dutasteride, other 5α-reductase inhibitors, soy, peanuts or other components of the drug.

Not suitable for use in women and children (see Use during pregnancy and lactation ). Dutasteride is contraindicated in patients with severe hepatic impairment.

monotherapy with Avodart . According to 3 placebo-controlled phase III clinical trials with dutasteride compared with placebo, the following adverse reactions were noted, which, according to the researchers, were associated with the use of the drug (with an incidence of ≥1%).

*Adverse reactions associated with sexual dysfunction associated with dutasteride treatment (including monotherapy and combination with tamsulosin). These adverse reactions may continue after treatment is stopped. The effect of dutasteride on their duration is unknown.

**Including breast tenderness and hypertrophy.

The following 2-year open-label clinical trial showed no change in the side effect profile of the drug.

Combination therapy (Avodart + tamsulosin) . According to the CombAT clinical trial (combination of Avodart with tamsulosin), comparing the combination of Avodart 0.5 mg and tamsulosin 0.4 mg 1 time per day and monotherapy for 4 years, revealed such adverse reactions that, according to the researchers, were associated with the use of the drug (with a cumulative incidence of ≥1%).

Adverse reactions	Frequency of occurrence during treatment,%
	Year 1	Year 2	Year 3	4th year
Combination a (n) Dutasteride Tamsulosin	(n=1610) (n=1623) (n=1611)	(n=1428) (n=1464) (n=1468)	(n=1283) (n=1325) (n=1281)	(n=1200) (n=1200) (n=1112)
Impotence b
combination a	6. 3	1.8	0.9	0.4
Dutasteride	5.1	1.6	0.6	0.3
Tamsulosin	3.3	1.0	0.6	1.1
Change (decrease) in libido b
combination a	5.3	0.8	0.2	0
Dutasteride	3.8	1	0.2	0
Tamsulosin	2.5	0.7	0.2	<0.1
Ejaculatory disorders b
combination a	9	1	0.5	<0.1
Dutasteride	1.5	0.5	0.2	0.3
Tamsulosin	2.7	0.5	0.2	0. 3
Breast dysfunction c
Combination a	2.1	0.8	0.9	0.6
Dutasteride	1.7	1.2	0.5	0.7
Tamsulosin	0.8	0.4	0.2	0
Heart failure d
combination a	0.2	0.4	0.2	0.2
Dutasteride	<0.1	0.1	<0.1	0
Tamsulosin	<0.1	<0.1	0.4	0.2
Dizziness
combination a	1.4	<0.1	<0.1	0.2
Dutasteride	0.7	<0.1	<0. 1	<0.1
Tamsulosin	1.3	<0.4	<0.1	0

^a Combination of dutasteride 0.5 mg once daily plus tamsulosin 0.4 mg once daily.

^b Adverse reactions associated with impaired sexual function are associated with treatment with dutasteride (including monotherapy and combination with tamsulosin). These adverse reactions may continue after treatment is stopped. The effect of dutasteride on their duration is unknown.

^c Including breast tenderness and hypertrophy.

^d The term “heart failure” includes congestive heart failure, left ventricular failure, acute left ventricular failure, cardiogenic shock, acute heart failure, right ventricular failure, acute right ventricular failure, congestive cardiomyopathy, cardiopulmonary failure, ventricular failure.

Post-marketing data

Immune system: very rarely – allergic reactions, including rash, itching, urticaria, localized edema and angioedema.

Mental disorders: very rare – depressive mood.

Skin and subcutaneous tissue: rarely – alopecia (mainly loss of body hair), hypertrichosis.

Reproductive system and breast disorders: very rarely – testicular pain and swelling.

Cases of breast cancer have been reported in men in clinical and post-marketing studies (see SPECIAL INSTRUCTIONS).

dutasteride may be absorbed through the skin, so women and children should avoid contact with leaky capsules (see Pregnancy and Lactation ). If the liquid from the capsule gets on the skin, it should be washed off immediately with soap and water.

The effect of hepatic impairment on the pharmacokinetics of dutasteride has not been studied. Since dutasteride is extensively metabolized and its T _½ is 3-5 weeks, the drug should be used with caution in patients with mild to moderate hepatic impairment (see USE and PHARMACOLOGICAL PROPERTIES).

Adverse reactions from the cardiovascular system . Combination therapy may be prescribed after a careful benefit/risk assessment due to the potential increased risk of adverse reactions (including heart failure) and after consideration of alternative treatment options, including monotherapy.

Based on 4-year clinical trials, the incidence of heart failure (combined term for all reports, predominantly heart failure and congestive heart failure) was higher among patients treated with the combination of Avodart with an α-adrenergic blocker, mainly tamsulosin, compared with patients who did not use this combination. In these two studies, the incidence of heart failure was low (≤1%) and variable within these studies. There is no disproportion in the incidence of cardiovascular side effects in any of the studies. A causal relationship between the use of Avodart (alone or in combination with α-adrenergic blockers) and the occurrence of heart failure has not been established (see PHARMACOLOGICAL PROPERTIES).

Effect on PSA . The PSA concentration is an important component of the screening process for prostate cancer.

Avodart is able to reduce plasma PSA levels in patients by an average of 50% after 6 months of treatment.

In patients taking Avodart, a new baseline PSA level should be determined 6 months after treatment with this drug. Subsequently, this level is recommended to be checked regularly. Any confirmed increase in PSA from its lowest point with Avodart may be indicative of prostate cancer or non-compliance with Avodart and should be carefully investigated, even if PSA values ​​are within normal limits in men not treated with 5α-reductase inhibitors. When interpreting PSA values ​​in patients taking Avodart, previous PSA values ​​should be taken into account for comparison.

The use of Avodart does not affect the use of PSA to diagnose prostate cancer once a new baseline has been established.

Total plasma PSA returns to baseline within 6 months of stopping treatment.

The ratio of free PSA to total PSA remains constant even with Avodart. Therefore, if the doctor decides to use the percentage of free PSA to determine prostate cancer in a patient taking Avodart, correction of its value is not required.

Before starting a course of treatment with dutasteride and periodically during therapy, a digital rectal examination of the patient should be performed, as well as other methods for detecting prostate cancer should be used.

Prostate cancer and high Gleason grade tumors (poorly differentiated) . In a 4-year clinical trial of >8000 men aged 50-75 years with pre-negative biopsy for prostate cancer and a baseline PSA level of 2.5-10.0 ng/mL (REDUCE study), 1517 diagnosed with prostate cancer. The incidence of prostate cancer (8–10 points on the Gleason scale) in the group of patients treated with Avodart (n=29, 0.9%) was higher compared to the placebo group (n=19, 0.6%). An increase in the incidence of prostate cancer on the Gleason scale of 5–6 and 7–10 points was not noted. A causal relationship between the use of Avodart and high stages of prostate cancer has not been established. The clinical significance of the numerical imbalance is unknown. Men taking Avodart should be regularly screened for risk of prostate cancer, including PSA.

An additional 2-year follow-up study in patients enrolled in the dutasteride chemoprophylaxis study (the REDUCE study) found a low incidence of new prostate cancer cases (dutasteride group [n=14, 1.2%] and placebo group [n=7, 0.7%]) with no new identified cases of prostate cancer with a Gleason score of 8–10.

Long-term follow-up (up to 18 years) of patients from a clinical study using another 5α-reductase inhibitor (finasteride) as chemoprophylaxis did not show a statistically significant difference between the finasteride and placebo groups in the overall survival rate (HR 1.02; 95% CI 0.97–1.08) or survival after diagnosis of prostate cancer (HR 1.01; 95% CI 0.85–1.20).

Breast cancer . Rare cases of breast cancer have been reported in men during clinical trials and in the post-marketing period. At the same time, epidemiological studies indicate that there is no increase in the risk of developing breast cancer in men when using 5α-reductase inhibitors. Patients should immediately report any changes in breast tissue, such as nipple discharge or swelling.

Leaky capsules . Dutasteride is absorbed through the skin, so women and children should avoid contact with leaky capsules. If the liquid from the capsule gets on the skin, it should be washed off immediately with soap and water.

Liver failure . The effect of hepatic impairment on the pharmacokinetics of dutasteride has not been studied. Due to the active metabolism of dutasteride and the 3-5 week T _½ , treatment with dutasteride in patients with mild or moderate hepatic insufficiency should be carried out with caution (see USE, CONTRAINDICATIONS, PHARMACOLOGICAL PROPERTIES).

Use during pregnancy and lactation

Fertility . Study of the effect of dutasteride at a dose of 0.5 mg/day on ejaculate characteristics in 27 healthy volunteers aged 18–52 years (n=27 in the dutasteride group, n=23 in the placebo group) during 52 weeks of treatment and 24 weeks of follow-up observations showed a decrease in total sperm count, ejaculate volume and sperm motility by 23; 26 and 18% compared to changes in the placebo group. The concentration of sperm and its morphology remained unchanged. After 24 weeks of follow-up, the mean percent change in total sperm count in the dutasteride group remained 23% below baseline. While the mean values ​​for all sperm parameters at all time intervals remained within the normal range and did not meet certain criteria for clinically significant changes (30%), two patients in the dutasteride group had a decrease in sperm count of more than 90% compared with the baseline at the 52nd week of treatment and with a partial recovery of their number after 24 weeks of follow-up. The clinical significance of the effect of dutasteride on semen characteristics for individual patient fertility is unknown.

Pregnancy . Dutasteride is contraindicated for the treatment of women. The use of dutasteride for the treatment of women has not been studied because, according to preclinical studies, it has been suggested that suppression of the level of circulating dihydrotestosterone can inhibit the development of the external genitalia in the male fetus that the woman bears.

Breastfeeding . It is not known whether dutasteride passes into a woman’s breast milk.

The ability to influence the reaction rate when driving vehicles or working with other mechanisms . Taking into account the pharmacokinetic and pharmacodynamic properties, dutasteride does not affect the ability to drive a car and other mechanisms.

Since dutasteride is metabolized by the CYP 3A4 isoenzyme, the plasma concentration of dutasteride may increase in the presence of CYP 3A4 inhibitors. Long-term administration of dutasteride with drugs that are strong inhibitors of the CYP 3A4 enzyme (such as ritonavir, indinavir, nefazodone, itraconazole, oral ketoconazole) may lead to an increase in the concentration of dutasteride. According to the study, the clearance of dutasteride is reduced when used simultaneously with CYP 3A4 inhibitors verapamil (37%) and diltiazem (44%). However, the clearance of dutasteride is not reduced when used with amlodipine, another calcium channel antagonist.

The decrease in clearance and the corresponding increase in the effect of dutasteride in the presence of CYP 3A4 inhibitors is of little clinical importance due to the wide spectrum of drug safety.

In vitro dutasteride is not metabolized by CYP 1A2, CYP 2A6, CYP 2E1, CYP 2C8, CYP 2C9, CYP 2C19, CYP 2B6 and CYP 2D6 isoenzymes of the human cytochrome P450 system.

Dutasteride does not inhibit isoenzymes of the cytochrome P450 system in humans in vitro and does not induce CYP 1A, CYP 2B and CYP 3A isoenzymes in rats and dogs in vivo .

In vitro studies have shown that dutasteride does not displace warfarin, acenocoumarol, phenprocoumon, diazepam, or phenytoin from plasma protein binding, nor do these components replace dutasteride. Interactions of dutasteride with tamsulosin, terazocin, warfarin, digoxin, and cholestyramine have been studied. No clinically significant interaction was found.

Although no specific drug interaction studies have been conducted, about 90% of all patients during clinical trials of dutasteride received other drugs. No clinically significant adverse reactions were noted with the simultaneous use of dutasteride with antihyperlipidemic drugs, ACE inhibitors, β-adrenergic blockers, calcium channel blockers, corticosteroids, diuretics, NSAIDs, type V PDE inhibitors and quinoline antibiotics.

According to clinical studies, in volunteers, single doses of dutasteride up to 40 mg / day (80 times higher than therapeutic) for 7 days did not cause concern in terms of the safety of their use.