Metronidazole: MedlinePlus Drug Information

pronounced as (me troe ni’ da zole)

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Metronidazole can cause cancer in laboratory animals. Talk to your doctor about the risks and benefits of taking this medication.

Metronidazole capsules and tablets are used to treat infections of the reproductive system, gastrointestinal (GI) tract, skin, heart, bone, joint, lung, blood, nervous system, and other areas of the body. Metronidazole capsules and tablets are also used to treat sexually transmitted diseases (STDs). Metronidazole extended-release (long-acting) tablets are used to treat bacterial vaginosis (an infection caused by too much of certain types of harmful bacteria in the vagina) in women. Metronidazole is in a class of medications called nitroimidazole antimicrobials. It works by stopping the growth of bacteria.

Antibiotics will not work for colds, flu, or other viral infections. Using antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.

Metronidazole comes as a tablet, an extended-release tablet, and as a capsule to take by mouth. Metronidazole capsules and tablets are usually taken as a one-time dose (or divided into two doses on 1 day) or two to four times daily for up to 10 days or longer. Metronidazole extended-release tablets are usually taken once daily at least 1 hour before or 2 hours after a meal for 7 days. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take metronidazole exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the extended-release tablets whole; do not split, chew, or crush them.

Continue to take this medication even if you feel well. Do not stop taking it without talking to your doctor. If you stop taking this medication too soon or skip doses, your infection may not be completely treated and the bacteria may become resistant to antibiotics.

Metronidazole tablets are used to treat bacterial vaginosis in women.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking metronidazole,

• tell your doctor and pharmacist if you are allergic to metronidazole, secnidazole (Solosec), tinidazole (Tindamax), any other medications, or any of the ingredients in metronidazole preparations. Ask your pharmacist for a list of the ingredients.
• tell your doctor if you are taking or have taken disulfiram (Antabuse). Your doctor may tell you not to take metronidazole if you are taking disulfiram or have taken it within the past 2 weeks.
• tell your doctor and pharmacist what prescription, nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: anticoagulants (‘blood thinners’) such as warfarin (Coumadin, Jantoven), busulfan (Busulfex, Myleran), cimetidine (Tagamet HB), lithium (Lithobid), phenobarbital, and phenytoin (Dilantin, Phenytek).
• tell your doctor if you have or have ever had Crohn’s disease, or blood, kidney, or liver disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking metronidazole, call your doctor. Women who are pregnant generally should not take metronidazole during the first trimester (first 3 months) of pregnancy.
• do not drink alcoholic beverages or take products with alcohol or propylene glycol while taking this medication and for at least 3 days after your final dose. Alcohol and propylene glycol may cause nausea, vomiting, stomach cramps, headache, sweating, and flushing (redness of the face) when taken with metronidazole.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Metronidazole may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• vomiting
• nausea
• diarrhea
• constipation
• upset stomach
• stomach cramps
• loss of appetite
• headache
• dry mouth
• sharp, unpleasant metallic taste
• furry tongue; mouth or tongue irritation

Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:

• numbness, pain, burning, or tingling in your hands or feet
• seizures
• rash
• itching
• hives
• peeling or blistering skin
• flushing
• stuffy nose, fever, sore throat, or other signs of infection
• joint pain
• dizziness
• difficulty speaking
• problems with coordination
• confusion
• agitation

Metronidazole may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light, excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

• nausea
• vomiting
• loss of muscle coordination
• numbness, pain, burning, or tingling in your hands or feet
• seizures

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Side effects, dosage, uses, and more

Metronidazole oral tablets and capsules have a black box warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning indicates drug effects that may be dangerous.

• Cancer warning: Cancer was found in some animals during testing with metronidazole. There may be a similar risk in humans. Because of this risk, metronidazole should only be used to treat conditions as approved by the FDA.
• Usage warning: To reduce the occurrence of drug-resistant bacteria, metronidazole should only be used to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

1. Metronidazole oral tablets are available as both generic and brand-name drugs. Brand names: Flagyl (immediate-release), Flagyl ER (extended-release).
2. Metronidazole comes in several forms. These include an oral tablet, an oral capsule, a cream, gel, and lotion you apply to your skin, and a vaginal gel. It also comes as an injectable medication given by a healthcare professional.
3. Metronidazole oral tablets are used to treat infections caused by bacteria or parasites.

The metronidazole immediate-release tablet and extended-release tablet are prescription drugs. They’re both taken by mouth. These tablets are available as the brand-name drugs Flagyl (immediate-release) and Flagyl ER (extended-release).

Immediate-release drugs are released into the body right away. Extended-release drugs are released into the body slowly over time.

Both the immediate-release and extended-release tablets are available as generic drugs. Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in all strengths or forms as the brand-name drug.

Why it’s used

Metronidazole is used to treat various infections caused by bacteria or parasites. These include gastrointestinal, reproductive, or vaginal infections.

Metronidazole may be used as part of combination therapy. This means you may need to take it with other medications.

How it works

Metronidazole belongs to a class of drugs called nitroimidazole antimicrobials. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Antimicrobials are drugs used to treat infections. Nitroimidazole antimicrobials treat infections caused by bacteria and other organisms called protozoa. Metronidazole tablets work by killing the bacteria or other organisms that are causing the infection. This relieves the infection.

Metronidazole can cause side effects.

More common side effects

The more common side effects that can occur include:

• headache
• loss of appetite
• nausea or vomiting
• diarrhea
• heartburn
• cramping in your stomach area
• constipation
• metallic taste

These effects may go away within a few days or a couple of weeks if they are mild. Talk with your doctor or pharmacist if they’re more severe or don’t go away.

Serious side effects

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

• Nervous system effects, including seizures and encephalopathy (abnormal brain function). Symptoms can include:
  • convulsions (sudden movements caused by tightening of your muscles)
  • dizziness
  • headache
  • confusion
  • ataxia (loss of control of body movements)

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 professional who knows your medical history.

Side effects for males vs. females

For the most part, the side effects of metronidazole for males and females are the same. The only real differences in side effects affect females. For instance, metronidazole increases the risk of yeast infections, which occur much more often in females. Also, metronidazole can cause vaginal irritation and discharge.

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Metronidazole oral tablet 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 carefully manage your medications. Be sure to tell your doctor about all your medications, vitamins, or herbs. Talk with your doctor or pharmacist to find out how this drug might interact with something else you’re taking.

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

Drugs you should not take with metronidazole

Disulfiram: Do not take disulfiram with metronidazole. Doing so can cause dangerous effects on your body. Using it with metronidazole can cause psychotic reactions. Symptoms can include:

• confusion
• hallucinations (seeing or hearing things that aren’t real)
• delusions (believing things that aren’t real)

Do not take metronidazole if you’ve taken disulfiram in the last two weeks.

Interactions that increase your risk of side effects

Taking metronidazole with certain medications raises your risk of side effects. This is because the amount of either drug may be increased in your body. Examples include:

• Lithium: Increased side effects are related to raised lithium levels. Your doctor should monitor your lithium levels if you take these drugs together.
• Warfarin or other blood thinners: Increased side effects of these drugs include a higher risk of bleeding.
• Busulfan: If possible, you should avoid taking busulfan with metronidazole. If you do take these drugs together, your doctor may check the amount of busulfan in your body more often.
• Cimetidine: Taking cimetidine with metronidazole may result in higher metronidazole levels in your body and increased side effects.
• Phenytoin or phenobarbital: Taking one of these drugs with metronidazole may reduce your body’s metronidazole levels. This could prevent metronidazole from curing your infection.

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 professional about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

All possible dosages and drug 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
• the severity of your condition
• other medical conditions you have
• how you react to the first dose

For bacterial and protozoal infections

Generic: Metronidazole

• Form: immediate-release oral tablet
• Strengths: 250 mg, 500 mg

Brand: Flagyl

• Form: immediate-release oral tablet
• Strengths: 250 mg, 500 mg

Adult dosage (ages 18–64 years)

Your dosage and length of treatment depend on your infection type.

Bacterial infections:

• Typical dosage: 500 mg two to four times per day for up to 14 days. However, some infections may require longer treatment.
• Maximum dosage: 4 g per day.

Amoebic infections:

• Typical dosage: 500 mg or 750 mg three times per day for 5–10 days.

Trichomoniasis:

• Typical dosage: Either 2 grams (g) as a single dose or two divided doses of 1 g each on a single day, or 250 mg three times per day for 7 days.

Child dosage (ages 0–17 years)

Amoebic infections:

• Typical dosage: 35–50 mg/kg of body weight per day given in three divided doses for 10 days.

Senior dosage (ages 65 years and older)

The kidneys and liver of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for longer. This increases your risk of side effects. Your doctor may start you on a lowered dose or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

For bacterial vaginosis

Generic: Metronidazole

• Form: extended-release oral tablet
• Strengths: 750 mg

Brand: Flagyl ER

• Form: extended-release oral tablet
• Strength: 750 mg

Adult dosage (ages 18–64 years)

• Typical dosage: 750 mg per day for 7 days.

Senior dosage (ages 65 years and older)

The kidneys and liver of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dose or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

FDA warnings

• Metronidazole oral tablets and capsules have a black box warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning indicates drug effects that may be dangerous.
• Cancer warning: Cancer was found in some animals during testing with metronidazole. There may be a similar risk in humans. Because of this risk, metronidazole should only be used to treat conditions as approved by the FDA.
• Usage warning: To reduce the occurrence of drug-resistant bacteria, metronidazole should only be used to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

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Nervous system effects warning

Metronidazole oral tablets may cause certain serious conditions that affect the nervous system. These conditions include:

• encephalopathy (abnormal brain function)
• meningitis (inflammation in the brain)
• seizures
• peripheral neuropathy (nerve damage in the hands and feet)

Call your doctor right away if you have symptoms such as:

• memory loss
• trouble focusing
• fever
• stiff neck
• pain or numbness in your hands or feet

Allergy warning

Metronidazole can cause a severe allergic reaction or hypersensitivity. Symptoms can include:

• hives (itchy welts)
• red rash
• peeling or sloughing of your skin
• wheezing
• fever
• chills

Call your doctor or local poison control center immediately if you have an allergic reaction. 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. In some cases, taking it again could lead to death.

Alcohol interaction warning

You should stop using drinks that contain alcohol at least 3 days before starting metronidazole. Also, avoid alcohol for 3 more days after you stop treatment with this drug.

This is because alcohol can cause side effects when used with metronidazole. These include:

• nausea
• vomiting
• abdominal cramps
• headaches
• flushing (sudden redness and warmth in your face)

If you drink alcohol, talk with your doctor about whether this drug is safe for you.

Warnings for certain groups

For people with liver disease: Your liver helps process this drug. If you have severe liver disease, your liver may process this drug more slowly. This would increase the amount of the drug in your body and raise your risk of side effects. Your doctor may lower your dosage of metronidazole or have you take it less often.

For people with kidney disease: Your kidneys help clear this drug from your body. If you have severe kidney disease, your kidneys may process this drug more slowly. This increases the amount of the drug in your body and raises your risk of side effects. Your doctor may lower your dose of metronidazole or have you take it less often.

For pregnant people: Talk with your doctor if you’re pregnant or planning to become pregnant. Studies of the drug in pregnant animals have not shown a risk to the fetus. There aren’t enough studies on pregnant people to show if the drug poses a risk to humans.

Metronidazole should not be taken during the first trimester of pregnancy. For the second and third trimesters, this drug should be used only if the potential benefit justifies the potential risk.

For people breastfeeding or chestfeeding: Metronidazole may pass into breast milk and cause side effects in a child who is nursing. Talk with your doctor if you nurse your child. You may need to decide whether to stop nursing or stop taking this medication.

For seniors: The kidneys and liver of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Metronidazole tablets are used for short-term treatment. They come with risks if you don’t take them as prescribed.

If you stop taking the drug suddenly or don’t take it at all: Your infection may not improve and may get worse.

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. Symptoms of an overdose can include increased side effects, such as:

• headache
• loss of appetite
• nausea or vomiting
• diarrhea
• heartburn
• cramping in your stomach area
• constipation
• metallic taste

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 1-800-222-1222 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: Your symptoms of infection should improve.

General

• You can take the immediate-release tablets with or without food. Taking them with food may help reduce an upset stomach.
• Do not take the extended-release tablets with food. You should take them at least 1 hour before a meal or 2 hours after a meal.
• You can cut or crush the immediate-release tablets. However, do not cut or crush the extended-release tablets.
• Take metronidazole at the time(s) recommended by your doctor.

Storage

• Store this drug at a temperature below 77°F (25°C).
• Keep it 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, follow these tips:

• 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 can’t hurt your medication.
• You may need to show airport staff the pharmacy label for your medication, so 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.

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

Q:

Is it safe to use metronidazole and birth control together?

I asked

A:

Metronidazole oral tablet is safe to use with hormonal birth control methods. While one type of antibiotic (rifampin) is known to cause problems with some birth control, it’s not an issue with metronidazole. No research shows that this drug can make you more likely to get pregnant if you’re using the pill or other types of hormonal birth control.

Of course, if you have concerns, be sure to ask your doctor. And you can always use a backup method of birth control, such as a condom, while you’re taking metronidazole. To learn more, check out this article, which gives additional information about antibiotics and birth control.

The Medical News Today Medical TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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Disclaimer: Medical News Today 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 another 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.

Metronidazole Compendium – drug guide

Metronidazole , which has been widely used for many years to treat trichomoniasis, amebiasis and jardiasis, has recently shown activity against anaerobic bacteria. Serum, cerebrospinal fluid and tissue concentrations are bactericidal, the required concentration is reached after the usual doses administered orally or intravenously, or higher doses administered rectally (suppository). Prospective studies (dividing study participants into groups who will or will not receive the test substance) have shown that the addition of metronidazole to preoperative bowel preparation regimens reduces the incidence of postoperative infection and eliminates anaerobic infection. Similarly, anaerobic infection after acute appendectomy or hysterectomy was virtually eliminated with metronidazole given before and for 1 week after surgery. Metronidazole has been successfully used to treat anaerobic infections of the chest, head, gastrointestinal tract and genitourinary system, as well as anaerobic septicemia and bacteremia.

Metronidazole is the most active drug available against obligate anaerobes and is likely to be of great value in the treatment of serious infections caused by these organisms. Although the lack of formal comparative studies in many areas of its use makes it difficult to clearly determine the relative therapeutic efficacy of metronidazole compared with other drugs such as clindamycin, chloramphenicol or penicillin, it is nevertheless a very effective tool for the treatment and prevention of anaerobic infections.

Antimicrobial activity: metronidazole, like other nitroimidazoles such as tinidazole, is active in vitro against obligate anaerobes, but does not show clinically significant activity against facultative anaerobes, obligate aerobes or microaerophilic bacteria, except Campylobacter 9000 5 fetus . At concentrations that are easily achieved in serum after oral, rectal or intravenous administration, metronidazole is active against Bacteroides fragilis and B. melaninogenicus , Fusobacterium spp. , Clostridium perfringens and other species Clostridium . However, it is generally less active against non-spore-forming Gram-positive bacteria such as Actinomyces spp. , Propionibacterium spp. , Bifidobacterium spp. and Eubacterium sp. ; it is also slightly less active against Gram-positive cocci ( Peptostreptococcus and Peptococcus spp. ), but less sensitive strains are usually not obligate anaerobes. Against susceptible organisms, metronidazole is usually bactericidal at concentrations equal to or slightly above the minimum inhibitory concentration.

Mechanism of action

. Exact mechanism of action Metronidazole is unclear, but it appears that once it enters the cell, it is somehow reduced and bound to deoxyribonucleic acid.

Toxicological studies

. Long-term toxicity of metronidazole has been considered in strains of mice and various animal species, however, neurological disorders appear in dogs not observed in other animal species. High oral doses caused weight loss and testicular atrophy in one strain of mice and in rats, while intravenous metronidazole did not affect the rate of weight gain in rats and did not cause any significant changes in blood pressure or hematological or biochemical parameters. Histological changes in the liver without associated changes in the level of enzymes in the blood serum were detected in monkeys receiving high doses. Doses up to 1 g/kg body weight per day for 5 weeks did not cause a dominant lethal effect in mice. An increased incidence of lung tumors and malignant lymphomas has been reported in Swiss mice studied in one laboratory, but not in species 9 rats. 0004 Sprague-Dawley or hamsters studied by other investigators. Further studies have not been able to demonstrate that Metronidazole induces DNA synthesis or is mutagenic in male mice as a result of an inherited translocation procedure.

A recent retrospective study by the Mayo Clinic found that the course of oncopathology in women treated with metronidazole for the treatment of infections T. vaginalis did not differ significantly from that in other women in this group without metronidazole, based on the observed number of cases in a larger population.

Pharmacokinetics

. Metronidazole appears to be readily absorbed after oral administration. Peak serum concentrations are reached 1-3 hours after a single dose, but serum levels vary depending on the assay method used. Microbiological analysis is advantageous as it indicates therapeutic activity but does not distinguish between the parent substance and some of its metabolites. After a single dose of 250 mg, the peak serum concentration is about 5 μg / ml, determined using gas-liquid chromatography. The bioavailability of metronidazole does not appear to be significantly reduced by concomitant food intake.

Distribution studies in healthy individuals and patients show that Metronidazole easily penetrates the cerebrospinal fluid and reaches therapeutic concentrations. Metronidazole has a high volume of distribution and is only slightly bound to serum proteins.

Metronidazole is excreted from the human body primarily by metabolism resulting from side chain oxidation, hydroxylation or conjugation of the parent compound. Within 24 hours after oral administration of metronidazole, the recovery of the total amount of nitro derivatives in the urine is 35–65% of the dose when determined by chemical analysis and 15–20% when using bioassay. In the biliary tract, metronidazole is found in hepatic bile at concentrations similar to those found in serum and at therapeutic concentrations in the gallbladder (no abnormalities). The reported half-life ranged from 6.2 to 11.5 hours in healthy subjects. The area under the serum concentration-time curve did not differ significantly in patients with normal or impaired renal function.

Metronidazole for anaerobic infections

. Anaerobes are responsible for various types of infections and are often found in clinical specimens of abdominal abscess, peritonitis, chest empyema, and female genital tract infections. Although the distinction between isolates that are commensals or contaminants and isolates that are true pathogens is sometimes difficult to distinguish from routine specimens, anaerobes have been shown to play a major role in postoperative infections associated with the abdominal cavity. Species Bacteroides is often isolated from abdominal abscesses and wounds and in mixed culture for infections associated with loss of intestinal mucosal integrity and operations on the female genital tract.

Metronidazole administered orally, rectally or intravenously has been successfully used to treat a wide range of intra-abdominal anaerobic infections, anaerobic infections resulting from operations and injuries of the female genital tract, anaerobic infections of the chest, anaerobic infections of the head (brain abscess), periodontal infections, otitis media, bone and joint infections, as well as anaerobic bacteremia and endocarditis (several cases). Sometimes the effectiveness of metronidazole was difficult to determine, since it was used in combination with antibacterial drugs active against aerobic and anaerobic bacteria. However, metronidazole was effective in the treatment of sepsis caused by anaerobic bacteria resistant to chloramphenicol and clindamycin and bacteremias that do not respond to clindamycin,

Metronidazole has been shown to be effective in anaerobic infections of the chest and anaerobic infections of the soft tissues of the pelvis in obstetrics and gynecology, but has not been compared in formal therapeutic studies with currently used antimicrobials. Of the several drugs available for the treatment of anaerobic pleuropulmonary infections, penicillin is the drug of choice for treating B. fragilis infection. Although some clinicians consider (large documentation) that clindamycin is the alternative of choice in penicillin-sensitive patients, others would prefer to use metronidazole.

For complex anaerobic pelvic infections, clinicians in some parts of the world will consider Metronidazole as the drug of choice over chloramphenicol and clindamycin, the current drugs of choice in other countries.

Because metronidazole readily enters the cerebrospinal fluid, some clinicians consider it to be superior to chloramphenicol in the treatment of anaerobic meningitis. Based on available data, it appears to be relatively non-toxic.

In endocarditis ( B. fragilis ) Metronidazole may become the drug of choice due to its rapid bactericidal action and should probably be included in the antimicrobial therapy regimen.

Prospective studies in patients undergoing elective colon surgery have shown that the administration of metronidazole before and for 7 days after surgery, in combination with other antimicrobials, significantly reduces the incidence of postoperative infection and eliminates anaerobic infection that does not cause sporulation. Wound infections caused by facultative organisms have occurred in some patients treated with metronidazole, but generally less frequently than in untreated patients.

Administration of metronidazole 1–2 g at admission and 200 mg 3 times daily for up to 7 days postoperatively reduced the incidence of infections and virtually eliminated anaerobic infection after emergency appendectomy or elective hysterectomy.

The indications for the use of prophylactic antibiotics in elective bowel surgery are still being debated, but studies using metronidazole in addition to kanamycin, neomycin, or phthalylsulfathiazole strongly suggest that anaerobic bacteria (especially Bacteroides sp. ) are the main factors of intra-abdominal and wound infection after colon surgery.

Side effects

. Rarely observed in patients treated with metronidazole for anaerobic infections. The use of doses exceeding the usual, led to rare cases of parasthesia of the feet and hands, peripheral neuropathy and epileptiform seizures. Further studies are needed to determine the frequency and nature of side effects that may occur with higher doses and longer duration of metronidazole treatment, sometimes necessary for the treatment of severe anaerobic infections.

Dosing regimen

. In the treatment of anaerobic infections, the usual adult oral dose is 400 mg 3 times a day for 7 days or longer according to clinical response. The oral dose for infants and children is 7.5 mg/kg body weight 3 times a day. When using rectal suppositories, adults should receive 1 g 3 times a day for 3 days, and then inject every 12 hours for 4 days, the corresponding pediatric (age 5-12 years) dose is 0.5 g (half the adult dose). Children aged 1 to 5 years should receive the 250 mg pediatric dose; for children under the age of 1 year, the dose is 125 mg.

By intravenous infusion, the usual adult dose is 500 mg in 100 ml of solution every 8 hours, administered at a rate of 5 ml per minute. For children under 12 years of age, the intravenous dose is 7.5 mg/kg body weight.

In the prevention of anaerobic infection in gynecological surgery, 1 g orally as a single dose before surgery and immediately after surgery 200 mg orally 3 times a day for up to 7 days is recommended. During planned surgical intervention on the colon Metronidazole has been successfully used with this schedule: 1 g as a single dose before surgery, after surgery 200 mg every 8 hours (if oral medications are possible, and if not, then 1 g rectally every 8 hours for periods when oral preparations are not possible, only 7 days of treatment) and when administered simultaneously with kanamycin or phthalylsulfathiazole (Brogden R. N. et al., 2012).

The Antabuse effect is often noted with the simultaneous use of alcohol. Contraindications are limited to the first trimester of pregnancy and hypersensitivity. Drug interactions (do not use concomitantly) include vitamin K antagonists, alcohol and phenytoin. Carcinogenesis and mutagenesis cannot be demonstrated in humans. Reports of bacterial resistance to metronidazole are virtually non-existent.

Although its role as part of a therapeutic regimen for the treatment of mixed aerobic/anaerobic infections has been reduced by newer, more expensive combination therapies, these new combinations have not shown any therapeutic benefit over metronidazole. Although the use of metronidazole has been reduced globally, it still plays an important role in these and other therapeutic applications. Many clinicians still consider metronidazole to be the gold standard antibiotic against which all other anaerobic antibiotics should be compared.

Analogues, what helps, side effects

THERE ARE CONTRAINDICATIONS. POSSIBLE SIDE EFFECTS. A SPECIALIST’S CONSULTATION IS REQUIRED. Antibiotics in capsules Antibiotics in tablets Antibiotic ointments

Author of the article

Anisimova Kristina Vasilievna,

Pharmacist

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Contents of the article 90 179

• Is metronidazole an antibiotic or not
• What does Metronidazole help with
• How to take Metronidazole
• Side effects of Metronidazole
• Metronidazole during pregnancy
• Metronidazole and alcohol
• Ask an expert on the topic of the article

In Europe alone, 25,000 cases per year do not work with antibiotics. People are dying. This is due to the development of resistance of microorganisms to commonly prescribed drugs. But while there is metronidazole, an antiprotozoal agent with an antibacterial effect, which causes resistance less often than other drugs.

Let’s tell you what it helps with, what side effects and contraindications it has, and also compare it with analogues.

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Metronidazole is an antibiotic or not

The drug has an antimicrobial effect, so experts are often asked the question: “Metronidazole is an antibiotic or not?”. Yes, Metronidazole is an antibiotic. However, it is primarily used as an antiprotozoal agent. It is 99% effective against Trichomonas, Amoebas and Giardia.

Metronidazole contains the active ingredient of the same name. Its mechanism of action is to block the DNA of microorganisms, because of which they die. The resistance of bacteria and protozoa to it develops much less frequently than to other antibiotics. For example, in bacteria C. difficile resistance to metronidazole is 1%, and to ciprofloxacin – 95%.

You may be interested in: Broad Spectrum Antibiotics for Children and Adults

What Metronidazole Helps

We list extensive indications for the use of Metronidazole:

• protozoan infections: Trichomonas vaginitis, Trichomonas urethritis, amoebiasis
• bone and joint infections, CNS infections (including meningitis, brain abscess), bacterial endocarditis, pneumonia
• abdominal infections (peritonitis, liver abscess), pelvic infections (endometritis, endomyometritis, fallopian tube and ovarian abscess, vaginal fornix infections after surgery), skin and soft tissue infections
• sepsis
• gastritis or duodenal ulcer associated with Helicobacter pylori colitis
• alcoholism
• prevention of postoperative complications
• radiation therapy of patients with tumors

Metronidazole is often prescribed:

• for inflammation of the uterus
• for cystitis in women (as a consequence of trichomoniasis)
• for moderately severe giardiasis without complications
• for diarrhea caused by susceptible bacteria
• for men with Trichomonas urethritis

How to take Metronidazole

Metronidazole is available in the following dosage forms and dosages:

• tablets 0. 25 g, 0.5 g
• solution for infusion 0.5%
• vaginal suppositories 0.5 g
• gel for external use 1%

Metronidazole tablets are taken before or after meals with plenty of water.

Dosing regimens for tablets and other forms depend on the diagnosis and severity of the disease, the dosage and duration of treatment are selected by the doctor.

Side effects of Metronidazole

When prescribing Metronidazole, the doctor should warn the patient about possible side effects and take into account contraindications.

The most common side effects are:

• diarrhea, anorexia, nausea, vomiting, intestinal colic, constipation, metallic taste in the mouth, dry mouth
• dizziness, incoordination
• allergic reactions: urticaria, skin rash, skin flushing, nasal congestion
• candidiasis, red-brown urine.

Metronidazole during pregnancy

The drug passes through the placental barrier and into breast milk. There are no data on the effect on the development of the fetus and child. In this regard, it is forbidden to use Metronidazole during pregnancy and during breastfeeding.

Metronidazole and alcohol

Metronidazole is incompatible with alcoholic beverages – if taken simultaneously, acute intoxication of the body develops. Possible consequences after a “cocktail” of alcohol and Metronidazole: redness of the face and body, increased blood pressure, trembling, vomiting. In some cases, death is possible.

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Consider analogues of the drug Metronidazole.

• Trichopolum. It contains the same active ingredient – Metronidazole. It is produced in Poland in the form of tablets of 0.25 g for internal use and in the form of vaginal tablets of 0.5 g. The indications and contraindications of the drugs are identical. Differences are only in the forms of release and manufacturers of substances. Both drugs are generics of the original metronidazole – Flagyl.
• Choosing which is better Metronidazole or Trichopolum is necessary taking into account the disease and the treatment regimen prescribed by the doctor. The effectiveness of the drugs is the same.
• Tinidazole is an antiprotozoal drug, like Metronidazole. It has a similar mechanism of action. Tinidazole is taken 1 time per day for up to three days. Metronidazole – 2-3 times a day for up to 7 days, depending on the indications.
• Difference between tinidazole and metronidazole: the former is used primarily for the treatment of infections caused by protozoa and is not used for bacterial infections. Metronidazole is the drug of choice for bacterial vaginosis.
• Ornidazole. The active substance is ornidazole, also an antiprotozoal agent. The difference with Metronidazole lies in the greater effectiveness of Ornidazole in trichomoniasis, in the convenience of using it in a short course and in the frequency of administration – 2 times a day for 3-5 days.