Side effects of antibiotics

Healthcare practitioners prescribe antibiotics to prevent and treat bacterial infections. Most of the side effects of taking antibiotics are not life threatening. However, antibiotics may cause severe side effects in some people that require medical attention.

Antibiotics are generally safe, and doctors prescribe them to stop the growth of bacteria; for example, to treat bacterial infections, such as strep throat, urinary tract infections (UTIs), and certain skin infections.

Antibiotics do not work against viruses that cause most upper respiratory infections, the common cold, or COVID-19.

For live updates on the latest developments regarding the novel coronavirus and COVID-19, click here.

However, antibiotics can cause side effects, ranging from minor to severe to life threatening. According to the Centers for Disease Control and Prevention (CDC), 1 in 5 medication-related emergency room visits are due to antibiotic side effects.

Anyone experiencing a severe antibiotic side effect should consult with a healthcare professional. A person experiencing anaphylaxis symptoms, such as difficulty breathing, chest pain, or tightness in the throat, should call 911.

This article explores common and rare side effects of antibiotics, including long term side effects and when to consult a doctor.

Learn more about bacteria here.

Whenever a person takes an antibiotic, they may experience some common side effects, such as:

Digestive problems

Digestive symptoms may include:

• nausea
• indigestion
• vomiting
• diarrhea
• bloating or feeling full
• loss of appetite
• stomach pain or cramping

Sometimes, a person needs to take antibiotics with food; other times, they need to take them on an empty stomach. A person can speak with their doctor or a pharmacist about how best to take their antibiotic.

Most digestive problems go away once a person stops taking the antibiotic.

Persons with digestive side effects, such as bloody diarrhea, severe abdominal pain, or uncontrollable vomiting, should stop taking their antibiotics and immediately contact a doctor.

Learn more about other common digestive disorders here.

Fungal infection

Antibiotics are drugs that kill harmful bacteria. However, they sometimes kill the good bacteria that protect people from fungal infections and upset the natural balance of the body’s natural flora.

As a result of this imbalance, taking antibiotics may lead to a fungal (candida) infection of the mouth, digestive tract, or vagina.

Candidiasis in the mouth and throat is also called thrush.

Symptoms of thrush may include:

• white patches on the throat, cheeks, roof of the mouth, or tongue
• pain while eating or swallowing
• bleeding with tooth brushing

Doctors usually prescribe antifungal medications such as nystatin to treat fungal infections.

Learn more about the gut microbiota here.

UTI antibiotics and yeast infections

Treating a UTI with antibiotics can sometimes lead to a vaginal yeast infection.

Symptoms of a vaginal yeast infection may include:

• vaginal itchiness, swelling, and soreness
• pain and a burning sensation during intercourse and when peeing
• abdominal or pelvic pain
• blood in the urine
• white-to-grey lumpy vaginal discharge
• fever and chills

Doctors often prescribe the antifungal drug fluconazole to treat yeast infections caused by UTI antibiotics.

Learn more about the safety of having sex and a UTI.

Drug interactions

Certain may interact with a person’s other medicines or supplements.

The symptoms of drug interactions range from mild to life threatening. Some common warning signs after taking the medication include:

• feeling nauseous
• feeling either very tired or very energetic

According to the Food and Drug Administration (FDA), drug interactions may make an antibiotic less effective or increase the action of a particular drug.

It is generally a good idea to avoid alcohol while taking antibiotics. Drinking alcohol while on certain antibiotics can decrease the effectiveness and increase the chance of antibiotic side effects.

Antibiotics that may interact with alcohol include:

• doxycycline
• erythromycin
• metronidazole
• tinidazole
• isoniazid

To help avoid antibiotic drug interactions, people should always review newly prescribed medications with their doctor or pharmacist. Patient education inserts also list any drugs that might interact with the prescribed antibiotic.

Learn more about alcohol and antibiotics here.

Photosensitivity

Certain medications, including antibiotics, make the skin more sensitive to sunlight. This is a condition called photosensitivity.

Photosensitivity symptoms include:

• discoloration of the skin, similar to the effects of sunburn
• inflammation
• itching
• blisters that resemble hives
• dry patches

Some antibiotics that may cause photosensitivity include ciprofloxacin, doxycycline, and levofloxacin.

While taking antibiotics that may cause photosensitivity, people should:

• avoid prolonged periods of light exposure, especially between the hours of 10.00 a.m.–4.00 p.m.
• use a broad sunscreen with an SPF value of 15 or above when outdoors, even on cloudy days
• wear protective clothing such as broad-brimmed hats, long-sleeved shirts, pants, and sunglasses to limit sun exposure

Anyone who experiences extreme sensitivity to the sun while taking antibiotics should talk with a doctor.

Learn about sunburn on dark skin here.

Staining

Research suggests that people who take tetracycline develop stains on their skin, nails, teeth, and bones. Doctors consider this a known but rare side effect of prolonged tetracycline use.

Teeth staining is irreversible in adults because their teeth do not regrow or change. However, as bones remodel themselves continuously, it is possible to reverse the staining.

A person should talk with a doctor about switching medications if taking antibiotics causes tooth discoloration or staining.

Learn more about stained teeth here.

Some of the more serious side effects associated with antibiotics include:

Anaphylaxis

In rare cases, antibiotics can cause an extremely severe allergic reaction known as anaphylaxis.

Signs of anaphylaxis include:

• a rapid heartbeat, when a person’s resting heartbeat is greater than 60–100 beats per minute
• hives or a red, itchy rash
• feelings of uneasiness and agitation
• tingling sensations and dizziness
• swelling of the face, mouth, and throat
• rapid swelling of the lips or under the skin
• severe wheezing, coughing, or trouble breathing
• low blood pressure
• fainting
• seizures

Anaphylaxis can be fatal without immediate emergency care. If people suspect anaphylaxis, they should dial the emergency services or go to the emergency room right away.

Learn more about the symptoms of anaphylactic shock here.

Clostridium difficile-induced colitis

C. difficile is a type of bacteria that can infect the large intestine and cause C. difficile-induced colitis, which causes intestinal inflammation and severe diarrhea.

Doctors find C-difficile-induced colitis challenging to treat because the bacterium is resistant to most antibiotics available.

Severe, chronic, or untreated cases of C-difficile-induced colitis can lead to death.

Anyone who has any concerns about developing an antimicrobial-resistant infection when taking antibiotics should talk with a doctor.

Learn more about antimicrobial resistance here.

Antibiotic resistance

Antibiotic resistance happens when germs develop the ability to overcome the antibiotic’s ability to kill them. That means the germs continue to grow.

Some infections caused by an antibiotic-resistant strain of bacteria do not respond to any available antibiotics. Antibacterial-resistant infections can be severe and potentially life threatening.

According to the Centers for Disease Control and Prevention (CDC), at least 2.8 million people in the United States contract antibiotic-resistant bacteria or fungi each year, and more than 35,000 people die as a result.

There are certain ways to help reduce the risk of developing antibiotic resistance, including:

• helping prevent the spread of infections by getting appropriate vaccinations, proper hand-washing, and staying home when sick
• following safe food preparation steps
• taking antibiotics exactly as the doctor prescribes if you need them
• talking with your doctor or pharmacist about ways to feel better if the infection does not require antibiotics
• never taking antibiotics that a doctor has prescribed for someone else
• never using leftover antibiotics or saving extra antibiotics
• returning unused antibiotics to a pharmacy or putting them in the trash

Learn how to dispose of medications safely here.

Kidney disease

According to the National Kidney Foundation, the kidneys clear many antibiotic medications.

When the kidneys are not working correctly, these medications can build up and lead to further kidney damage.

Doctors often check kidney function blood tests before prescribing antibiotics for individuals with kidney disease.

Learn about kidney failure here.

According to a study, long term side effects of antibiotics in adult females have links to changes in the gut microbiota. This change has links to risks of various chronic diseases, such as cardiovascular disease and certain types of cancer.

This study also states that the length of antibiotic exposure may be a risk factor for premature death.

Additional research also found that prolonged exposure to antibiotic therapy has associations with an increased risk of gastrointestinal issues in premature babies, late-onset sepsis, or death among very low birth weight infants.

Learn more about sepsis in babies here.

A doctor will usually confirm whether a person has a sensitivity or allergy to a particular antibiotic and will likely prescribe an alternative.

If a doctor prescribes an antibiotic, but the symptoms persist after a few days of taking it, a person should also consult a doctor.

However, anyone who has a severe side effect or allergic reaction while taking antibiotics should immediately stop taking the medications and seek medical attention.

Antibiotics are prescription medications that kill or prevent bacteria from growing. Doctors prescribe antibiotics to treat bacterial infections, such as strep throat or skin infections.

Antibiotics commonly produce side effects that range from mild to severe, so a person should only take them when a doctor deems them necessary.

People should report any antibiotic side effects to their doctor or healthcare professional.

Side Effects of Antibiotics

Introduction

Antibiotics are prescription drugs that help treat infections caused by bacteria. Some of the more common infections treated with antibiotics include bronchitis, pneumonia, and urinary tract infections.

Antibiotics work by killing the bacteria causing the infection, or by stopping the bacteria from growing and multiplying.

Antibiotics only work to treat bacterial infections. They don’t work for infections caused by viruses, which can include:

• common cold
• runny nose
• most coughs and bronchitis
• flu

There are many different groups, or classes, of antibiotics. These classes have side effects and typically affect men and women the same way. However, certain side effects are more common from some antibiotics than from others.

Read on to learn about common side effects, how to manage them, and which antibiotics are more likely to cause them.

Stomach upset

Many antibiotics cause stomach upset or other gastrointestinal side effects. These can include:

• nausea
• vomiting
• cramps
• diarrhea

Macrolide antibiotics, cephalosporins, penicillins, and fluoroquinolones may cause more stomach upset than other antibiotics.

What to do

Ask your doctor or pharmacist whether to take your antibiotic with food. Eating can help reduce stomach side effects from certain antibiotics such as amoxicillin and doxycycline (Doryx).

However, this approach won’t work for all antibiotics. Some antibiotics, such as tetracycline, must be taken on an empty stomach.

Talk to your doctor to make sure you know how you’re supposed to take your drug and if there are other ways you can ease stomach side effects.

When to call your doctor

Mild diarrhea usually clears up after you stop taking the drug. However, if the diarrhea is severe, it may cause:

• abdominal pain and cramping
• fever
• nausea
• mucus or blood in your stool

These symptoms can be caused by an overgrowth of harmful bacteria in your intestines. In these cases, call your doctor right away.

Photosensitivity

If you’re taking an antibiotic, such as tetracycline, your body can become more sensitive to light. This effect can make light seem brighter in your eyes. It can also make your skin more prone to sunburn.

Photosensitivity should go away after you finish taking the antibiotic.

What to do

If you know you’ll be out in the sun, take certain precautions to stay safe and comfortable.

Be sure to wear sunscreen with UVA and UVB protection, and reapply sunscreen as directed on the label.

Also, wear protective clothing and accessories, such as a hat and sunglasses.

Fever

Fevers are a common side effect of many medications, including antibiotics. A fever may occur because of an allergic reaction to a medication or as a bad side effect.

Drug fevers can occur with any antibiotic, but they’re more common with the following:

• beta-lactams
• cephalexin
• minocycline
• sulfonamides

What to do

If you get a fever while taking an antibiotic, it will likely go away on its own. But, if your fever doesn’t go away after 24 to 48 hours, ask your doctor or pharmacist about using over-the-counter pain relievers such as acetaminophen (Tylenol) or ibuprofen (Motrin) to help reduce the fever.

When to call your doctor

If you have a fever greater than 104°F (40°C), a skin rash, or trouble breathing, call your doctor or 911 right away.

Vaginal yeast infection

Antibiotics decrease the amount of a helpful bacteria, lactobacillus, in the vagina. This “good bacteria” helps keep a naturally occurring fungus called Candida in check. When this natural balance is tipped in favor of Candida growth a yeast infection may occur.

Symptoms include:

• vaginal itching
• burning during urination or sex
• swelling around the vagina
• soreness
• pain during sex
• redness
• rash

A whitish-gray and clumpy discharge from the vagina, sometimes said to look like cottage cheese, is another sign you have a yeast infection.

What to do

For simple yeast infections, your doctor may prescribe a vaginal antifungal cream, ointment, suppository, or an oral tablet. Examples include:

• butoconazole
• clotrimazole
• miconazole
• terconazole
• fluconazole

Many of the creams, ointments, and suppositories are also available without a prescription.

For severe or complicated yeast infections, your doctor may prescribe longer duration of medication treatment.

If the infection recurs, your sexual partner may also have a yeast infection. You should use condoms when having sex if you suspect either of you has a yeast infection.

Antibiotics such as tetracycline and doxycycline can cause permanent tooth staining in children whose teeth are still developing. This effect mostly occurs in children who are younger than 8 years of age.

If a pregnant woman takes these drugs, they may stain the developing child’s primary teeth.

What to do

Ask your doctor why they’re prescribing one of these antibiotics for you if you’re pregnant or for your child. Also, ask if there are other drug options that might work that don’t have this side effect.

Serious side effects from antibiotics aren’t common, but they can occur. Some of the main serious side effects include:

Allergic reactions

Allergic reactions are possible with any medication, including antibiotics. Some allergic reactions can be mild, but others can be serious and need medical attention.

If you’re allergic to a certain antibiotic, you’ll have symptoms right after taking the drug. These symptoms can include trouble breathing, hives, and swelling of your tongue and throat.

When to call your doctor

If you have hives, stop taking the drug and call your doctor. If you have swelling or trouble breathing, stop taking the drug and call 911 right away.

Stevens-Johnson syndrome

Stevens-Johnson syndrome (SJS) is a rare, but serious, disorder of the skin and mucous membranes. Mucous membranes are the moist linings of certain parts of your body, such as your nose, mouth, throat, and lungs.

SJS is a reaction that can happen with any medication, including antibiotics. It occurs more often with antibiotics such as beta-lactams and sulfamethoxazole.

Typically, SJS begins with flu-like symptoms, such as a fever or sore throat. These symptoms may be followed by blisters and a painful rash that spreads. Following that, the top layer of your skin can shed. Other symptoms can include:

• hives
• skin pain
• fever
• cough
• swelling of your face or tongue
• pain in your mouth and throat

What to do

You can’t prevent this condition, but you can try to reduce your risk.

You’re at increased risk for SJS if you have a weakened immune system, have had SJS in the past, or have a family history of SJS.

If you believe any of these conditions apply to you, talk to your doctor before taking an antibiotic.

When to call your doctor

Call 911 or go to the nearest emergency room right away if you have symptoms of SJS and think you have the condition.

Blood reactions

Some antibiotics can cause changes to your blood.

For example, leukopenia is a decrease in the number of white blood cells. It can lead to increased infections.

Another change is thrombocytopenia, which is a low level of platelets. This can cause bleeding, bruising, and slowed blood clotting.

Beta-lactam antibiotics and sulfamethoxazole cause these side effects more often.

What to do

You can’t prevent these reactions. However, you’re at higher risk if you have a weakened immune system. If your immune system is weak, discuss it with your doctor before you take an antibiotic.

When to call your doctor

Call your doctor if you have a new infection or one that appears abruptly after taking an antibiotic.

Call 911 or go to the nearest emergency room right away if you:

• have serious bleeding that doesn’t stop
• have bleeding from your rectum
• cough up a substance like coffee grounds

Heart problems

In rare cases, certain antibiotics can cause heart problems such as an irregular heartbeat or low blood pressure.

The antibiotics most often linked with these side effects are erythromycin and some fluoroquinolones such as ciprofloxacin. The antifungal terbinafine can also cause this problem.

What to do

If you have an existing heart condition, tell your doctor before you start taking any kind of antibiotic. This information will help your doctor choose the right antibiotic for you.

When to call your doctor

Call your doctor if you have new or worsening heart pain, an irregular heart rhythm, or trouble breathing. If your symptoms are severe, call 911 or go to the nearest emergency room.

Tendonitis

Tendonitis is inflammation or irritation of a tendon. Tendons are thick cords that attach bone to muscle, and they can be found throughout your body.

Antibiotics such as ciprofloxacin have been reported to cause tendonitis or tendon rupture. This is when the tendon tears or rips.

All people are at risk for tendon problems when taking certain antibiotics. However, certain people are at increased risk of tendon rupture. These include people who:

• have existing kidney failure
• have had a kidney, heart, or lung transplant
• have had past tendon problems
• are taking steroids
• are older than 60 years

What to do

Talk to your doctor before starting a new antibiotic if you meet any of the increased risk factors. This information will help your doctor choose the correct antibiotic for you.

When to call your doctor

If you have new or worsening tendon pain after taking your antibiotic, call your doctor. If the pain is severe, go to the nearest emergency room.

Seizures

It’s rare for antibiotics to cause seizures, but it can happen. Seizures are more common with ciprofloxacin, imipenem, and cephalosporin antibiotics such as cefixime and cephalexin.

What to do

If you have epilepsy or a history of seizures, be sure to tell your doctor before you start taking any kind of antibiotic. That way, your doctor can choose an antibiotic that won’t make your condition worse or interact with your seizure medications.

When to call your doctor

Call your doctor if you have new seizures or your seizures get worse when you take an antibiotic.

If your doctor prescribes antibiotics for you, know that there are ways to manage side effects. Some questions you may want to ask your doctor about antibiotic side effects include:

• Am I likely to have side effects with this drug?
• What are your suggestions for dealing with side effects?
• Are there any antibiotics that could help me that are known to have fewer side effects?

It may also help to show your doctor this article and discuss it. Together, you can manage any side effects you may have from your antibiotic.

Q:

If I have bad side effects from my antibiotic, can I stop taking the medication?

Anonymous patient

A:

That’s a big “No. ” You should never stop taking an antibiotic without first talking with your doctor.

Stopping an antibiotic treatment before it’s finished can cause the infection to return, perhaps even stronger than before. If it returns, it could be resistant to the antibiotic you were taking. That means the drug wouldn’t work to treat your infection.

Bad side effects from your antibiotic can be difficult, though, so call your doctor. They can suggest ways to reduce your side effects. If those don’t work, they may suggest another medication. The important part is to finish your full course of antibiotics.

Healthline 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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When to start taking antibiotics, the danger of self-medication with antibiotics

Do you still have friends who believe that antibiotics can kill the virus? We hope not. When is antibiotic therapy necessary? We asked Ksenia Solovieva, a therapist and endocrinologist, deputy chief physician of the Lahta Clinic on Kovno. Should you start taking antibiotics if you are sick and not recovering? Why can’t they be assigned to themselves?

Treatment with antibiotics is mandatory only for proven diseases of bacterial origin.

“I’ve been sick for 4 days and I can’t get better!”

The first thing to do is to visit a doctor and evaluate the red flags. The duration of symptoms is far from always a sign of a worsening course: for example, residual cough can persist for weeks (!) After the start of ARVI and not talk about the presence of complications or a severe course of the disease. The same applies to long-term subfebrile temperature (37-37.5 C) or weakness.

Unfortunately, in recent years, the respiratory viruses circulating in the population are quite “evil”, and not always ARVI is the standard 3-5 days of snot.

We evaluate the dynamics of the disease by the totality of signs and never prescribe antibiotic therapy simply because “we do not get better for a long time”.

High Temperature!

No reason to mindlessly take antibiotics. A clinically significant temperature increase, according to WHO, is 37.8 ° C and above. It is worth paying special attention if the temperature returned to normal, and then suddenly rose again after 7-10 days of illness. In both situations, see a doctor. Merely an increase in temperature or its turn is insufficient indications for prescribing antibiotics.

“Perhaps a bacterial infection has joined the virus!”

The notorious addition of a bacterial infection actually happens quite rarely outside the risk groups. These include children in their first year of life, the elderly and patients with chronic diseases. Therefore, for example, it is definitely worth vaccinating risk groups against pneumococcal infection.

We can prove the presence of a bacterial infection in the laboratory by evaluating the data of a clinical blood test and CRP, in rare cases (for example, with COVID-19and viral pneumonia) by evaluating the level of procalcitonin.

Depending on the expected localization of the pathological process – and to determine it at least a doctor is needed – instrumental diagnostic methods, such as x-rays, can be used.

When is antibiotic treatment useless?

When the causative agent of the disease is a virus, a fungus, or when we thoughtlessly take what the Internet has advised, without taking into account the spectrum of the drug. For example, a drug can be of a wide spectrum and “cover” many pathogens, but not accumulate in the proper amount in the affected organ we need.

Why can’t you prescribe antibiotics yourself?

• – Creation of super bacteria resistant to all existing types of antibacterial drugs
• – Antibiotic associated conditions, eg pseudomembranous colitis, severe bowel disease
• – Negative effects of a thoughtless combination of drugs on the heart and blood vessels

The combination of certain drugs may prolong the QT interval on the ECG. So, for example, the “popular” ones in the homemade Internet treatment of COVID-19 reinforce the negative effect of each other.levofloxacin and azithromycin are a direct road to ventricular arrhythmias, some of which can be fatal.

That is why the selection of antibiotic therapy requires a doctor, and sometimes a specially trained person – a clinical pharmacologist.

Allergy after antibiotics: symptoms, diagnosis – “Sensitive”

In recent years, doctors have noted an increase in the occurrence of allergic reactions to antibiotics both among adult patients and among children. In the medical center of Yeysk “Sensitive” you can undergo specific diagnostics to detect the allergen.

Allergies often appear suddenly after antibiotics, and there can be many reasons for this. The most common are the following:

1. Already existing allergy to food, pollen, dust.
2. Genetic predisposition.
3. Development in the body of such pathological processes as cytomegalovirus, mononucleosis.
4. Long-term use of antibiotics.
5. Long-term use of a drug.

In children, allergies after antibiotics develop with a weakened immune system, this can also be the cause of allergies in adults.

Allergy symptoms after antibiotics

Most often allergy after antibiotics occurs within the first day of administration. Much less often, immediate allergic reactions occur, and they develop within a few hours after the patient takes an antibiotic. In this case, the following manifestations will be observed:

• hyperemic rash, often like burns;
• tissue swelling and excruciating itching;
• difficulty in breathing;
• agonizing cough with wheezing;
• nausea which turns into vomiting;
• difficulty swallowing food.

In medicine, stages of an allergic reaction are distinguished, and at the mildest and medium stages, allergy after antibiotics manifests itself in the form of skin rashes, nausea, and swelling. With swelling of the nasopharynx, coughing, difficulty in swallowing food, difficulty breathing are manifested, and these symptoms should alert, because they may indicate Quincke’s edema. With this development of an allergic reaction, you should immediately contact the Yeysk “Sensitive” medical center, since this condition is life-threatening.

Anaphylactic shock is a severe stage of an allergic reaction, it develops rapidly, immediately after taking antibiotics, and requires emergency medical attention, therefore, with its symptoms, an ambulance should be called immediately.

Diagnosis of allergy after antibiotics

To diagnose allergies after antibiotics, special tests are used, which you can take at the medical center Yeysk “Sensitiv”:

• Specific Ab Ig E to Amoxicillin
• Specific Ab Ig E to Ampicillin
• Specific Ab Ig E to penicillin G
• Specific Ab Ig E to penicillin V

Various diagnostic methods are used in medicine.