Mary Choy, PharmD, is board-certified in geriatric pharmacotherapy. She currently serves as the director of pharmacy practice of the New York State Council of Health-System Pharmacists.

Biaxin XL (clarithromycin ) is an antibiotic used to treat various bacterial infections in many different parts of the body, including the lungs and skin. It also is used with other medicines to treat stomach ulcers caused by Helicobacter pylori (H. pylori). It can also prevent and treat disseminated mycobacterium avium complex (MAC) infection that affects people with human immunodeficiency virus (HIV).

Biaxin XL belongs to the class of medicines called macrolide antibiotics. Macrolide antibiotics interfere with bacteria’s ability to produce protein to kill or inhibit their growth. However, it does not work for colds, flu, and other viral infections.

Biaxin XL is a prescription medicine in extended-release (ER) tablet form. ER means that the tablet is made to release the medication in your body more slowly over time. 

Clarithromycin is also available as an immediate-release tablet and as a powder for suspension.

Brand Name: Biaxin, Biaxin Filmtab, Biaxin XL

Dosage Form: Tablet, extended-release tablet, powder for suspension

Biaxin XL is effective against a wide range of bacterial infections in different parts of the body. 

The Food and Drug Administration (FDA) approved Biaxin XL to treat:

It can also treat H. pylori, a bacterium that causes stomach ulcers when used in combination with medications called proton pump inhibitors.

Biaxin XL only treats bacterial infections. It does not work against colds, the flu, or other viruses. Taking an antibiotic unnecessarily may increase the risk of antibiotic resistance.

Biaxin XL is an ER tablet.

Take your medication for the prescribed amount of time, usually seven or 14 days. Take one tablet once every 24 hours with food, around the same time every day. Do not take more or less of a dose or take it more often than prescribed. Follow the directions on your prescription label carefully, and ask your healthcare provider to explain anything you do not understand. 

When taking the ER tablets, make sure to swallow them whole. Do not split, chew, or crush them. Your symptoms may begin to improve during the first few days of treatment. If the symptoms do not improve or if they get worse, contact your provider.

Do not stop taking Biaxin XL until you finish the prescription, even if you feel better. If you stop taking medicine before finishing your prescription or if you skip doses, the infection may return and lead to antibiotic resistance. If you experience any side effects, speak to your healthcare provider.

Store Biaxin XL tablets in an adequately closed container at room temperature, away from excess heat, moisture, and direct sunlight. Do not store it in a bathroom. Keep all medicines locked and out of the sight and reach of children and pets.

Dispose of any expired medication. Talk to your pharmacist about a medication return program to dispose of your medication properly. Do not throw away your unwanted or expired medication in a waste bin or flush it down the drain or toilet. 

Healthcare providers can prescribe clarithromycin to treat other types of infections. When a drug is prescribed for purposes not listed on the product label, it is known as off-label use. 

Clarithromycin may help treat other infections such as:

Make sure to only use Biaxin XL as prescribed by your provider. Never use it on your own without the advice of a healthcare professional.

This is not a complete list of side effects and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at www.fda.gov/medwatch or 800-FDA-1088.

As with other medications, Biaxin XL can cause side effects. Tell your healthcare provider about any side effects you have while using this medication. 

Common side effects of Biaxin XL include:

Consult a medical provider if any of these symptoms are severe or do not go away.

There can be some severe side effects. 

If any of the following symptoms occur, call your provider or get emergency medical treatment:

Biaxin XL may make you feel dizzy, confused, or disoriented. Avoid driving a car or operating machinery until you know how this medication affects you.

This medication may cause side effects other than those listed. Call your provider if you have any unusual problems while taking this medication.

Biaxin XL may rarely cause a severe intestinal infection due to a bacteria called Clostridium difficile (C. difficile) during treatment or even after weeks to months of treatment have stopped. Call your healthcare provider right away if you have severe diarrhea that doesn't stop, stomach pain, or blood or mucus in your stool. Do not use antidiarrheal or opioid products to relieve these symptoms, as they may worsen your condition. 

Prolonged use of this medication may result in oral thrush or a yeast infection. Consult your doctor or pharmacist if you see white patches in your mouth, a change in vaginal discharge, or other unusual symptoms.

Biaxin XL may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

If you have missed a dose of Biaxin XL, take it as soon as you remember it. If it's nearly the time for the next dose, skip the missed one and continue the next doses regularly. Do not take a double dose to make up for the missed one.

Taking too much Biaxin XL may result in gastrointestinal side effects such as stomach pain, vomiting, nausea, and diarrhea.

If you think you or someone else may have overdosed on Biaxin XL call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses, has a seizure, has trouble breathing, or can’t wake up after taking too much Biaxin XL, call 911 immediately.

It is very important that your doctor check your or your child's progress at regular visits to make sure this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.

Do not use this medicine if you or your child are also using astemizole (Hismanal®), cisapride (Propulsid®), lomitapide (Juxtapid®), lovastatin (Mevacor®), pimozide (Orap®), simvastatin (Zocor®), terfenadine (Seldane®), or certain ergot medicines (eg, dihydroergotamine, ergotamine, D.H.E. 45®, Ergomar®, Ergostat®, or Migranal®). If you have kidney or liver disease, do not take this medicine together with colchicine (Colcrys®). Using these medicines together may increase the risk for more serious side effects.

If your or your child's symptoms do not improve within a few days, or if they become worse, check with your doctor.

Make sure your doctor knows if you are pregnant or planning to become pregnant. If you become pregnant while using this medicine, tell your doctor right away.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and require immediate medical attention. Call your doctor right away if you or your child have a rash, itching, hoarseness, trouble breathing or swallowing, or any swelling of your hands, face, mouth, or throat while you or your child are using this medicine.

Serious skin reactions can occur with this medicine. Check with your doctor right away if you or your child have blistering, peeling, or loosening of the skin, red skin lesions, severe acne or skin rash, sores or ulcers on the skin, or fever or chills while you or your child are using this medicine.

Check with your doctor right away if you or your child have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, unusual tiredness or weakness, or yellow eyes or skin. These could be symptoms of a serious liver problem.

Contact your doctor right away if you have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you or anyone in your family has ever had a heart rhythm problem, such as QT prolongation.

Clarithromycin may increase the risk for heart and blood vessel problems in patients with these conditions. It may occur a year or 10 years after the use of this medicine. Talk to your doctor if you have concerns about this risk.

This medicine may cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you or your child stop taking this medicine. Do not take any medicine to treat diarrhea without first checking with your doctor. Diarrhea medicines may make the diarrhea worse or make it last longer. If you have any questions or if mild diarrhea continues or gets worse, check with your doctor.

This medicine may make you dizzy or confused. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

In some cases, your healthcare provider may choose not to prescribe this medication for you.

Before you start Biaxin XL, tell your healthcare provider if you have any of the following conditions:

Clarithromycin may harm the fetus. Use effective birth control while taking Biaxin XL. Also, let your healthcare provider know if you are having surgery, including dental surgery, while taking Biaxin XL. 

Biaxin XL is not recommended for use in children less than 6 months of age.

Combining certain medications with clarithromycin can affect how either medication works in the body. Some of these interactions can also affect your heart rhythm. Always tell your doctor or pharmacist about all the products you use, including prescription, nonprescription, vitamins, and herbal products. 

Biaxin XL should not be taken with:

Other drugs that can interact with Biaxin XL include:

Other medications that belong to the class of macrolide antibiotics include:

According to studies, clarithromycin is equally effective as erythromycin in treating community-acquired infections (infections acquired outside of a hospital setting). However, clarithromycin appears to be more tolerable due to fewer gastrointestinal side effects.

Biaxin XL (clarithromycin) is a macrolide antibiotic used to treat various infections, including pneumonia, cellulitis, and ear infections. It also treats ulcers caused by H. pylori infections.

Biaxin XL inhibits the ability of bacteria to make protein, which stops bacteria from multiplying.

The symptoms of various infections start to improve after a few days of treatment with this antibiotic. However, some infections may take longer to improve.

Common side effects of Biaxin XL are stomach pain, diarrhea, nausea, vomiting, heartburn, change in taste, and headache.

Always take your Biaxin XL for the prescribed number of days. Consult your healthcare provider before stopping the medicine prematurely. Stopping it early and skipping the doses can lead to drug resistance.

Biaxin XL is a relatively safe and effective antibiotic. Taking as prescribed helps prevent side effects and ensures that you receive maximum relief. Always try to take your medication for the prescribed amount of time to prevent antibiotic resistance. 

Biaxin XL is an extended-release tablet that slowly releases the medication as it passes through the digestive system to improve the symptoms of infection. 

Before taking medicine, consult with your healthcare provider about any other medications you are taking and other health conditions you have.

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

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Patel PH, Hashmi MF. Macrolides. In: StatPearls [Internet]. StatPearls Publishing; 2021.

U.S. National Library of Medicine. MedlinePlus. Clarithromycin.

Macrolide antibiotics. In: LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. National Institute of Diabetes and Digestive and Kidney Diseases; 2012.

Lebel M. Pharmacokinetic properties of clarithromycin: A comparison with erythromycin and azithromycin. Can J Infect Dis. 1993;4(3):148-152. doi:10.1155/1993/168061

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