Clarithromycin (By mouth)


Clarithromycin (kla-rith-roe-MYE-sin)

Treats and prevents infections. Also used in combination with other medicines to treat duodenal ulcers caused by H pylori. This medicine is a macrolide antibiotic.

Brand Name(s)

Biaxin XL, Prevpac, Biaxin Filmtab, Biaxin, Omeclamox-Pak

There may be other brand names for this medicine.

When This Medicine Should Not Be Used

Do not use this medicine if you have had an allergic reaction to clarithromycin, erythromycin (Ery-tab®), or other similar medicines (such as telithromycin, Ketek®). Do not use this medicine if you also use astemizole (Hismanal®), cisapride (Propulsid®), lovastatin (Mevacor®), pimozide (Orap®), simvastatin (Zocor®), terfenadine (Seldane®), or certain ergot medicines (such as dihydroergotamine, ergotamine, D.H.E. 45®, Ergomar®, Ergostat®, Migranal®). Do not use this medicine if you have a history of cholestatic jaundice or liver problems caused by clarithromycin, or a history of heart rhythm problems (such as QT prolongation, or ventricular arrhythmia, including torsades de pointes). Do not take this medicine together with colchicine (Colcrys®) if you have kidney or liver disease.

How to Use This Medicine

Liquid, Tablet, Long Acting Tablet

  • Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to.
  • Keep using this medicine for the full treatment time, even if you feel better after the first few doses. Your infection may not clear up if you stop using the medicine too soon.
  • While taking the extended-release form of this medicine, part of the tablet may pass into your stools. This is normal and is nothing to worry about.
  • Extended-release tablets: Biaxin® XL extended-release tablets should be taken with food. Swallow the extended-release tablet whole. Do not break, crush, or chew it.
  • Tablets: These may be taken with or without food. Swallow the tablet whole. Do not break, crush, or chew it.
  • Liquid (suspension): This may also be taken with or without food. Shake the bottle of medicine well right before you measure each dose. Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Do not refrigerate or freeze the oral liquid.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed. Throw away any leftover oral liquid 14 days after you fill the prescription.
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • This medicine can interfere with many other medicines. Make sure your doctor has a list of all other medicines you use. Tell him if you also use digoxin (Lanoxin®), itraconazole (Sporanox®), omeprazole (Prilosec®), rifabutin (Mycobutin®), rifampicin (Rifadin®, Rimactane®), rifapentine (Priftin®), theophylline (Theo-Dur®), tolterodine (Detrol®), a calcium channel blocker (CCB, blood pressure medicine, such as amlodipine, diltiazem, verapamil), medicine for heart rhythm problems (such as amiodarone, disopyramide, dofetilide, quinidine, procainamide, sotalol, Cordarone®, Norpace®), medicine to lower cholesterol (such as atorvastatin, fluvastatin, pravastatin, rosuvastatin, Lipitor®), medicine to treat diabetes (such as insulin, nateglinide, pioglitazone, repaglinide, rosiglitazone, Actos®, Avandia®, Prandin®), or a blood thinner (such as warfarin, Coumadin®, Jantoven®).
  • Do not use this medicine together with ranitidine bismuth citrate (Tritec®) if you have kidney disease or a history of porphyria.
  • Make sure your doctor knows if you also use medicine to treat HIV or AIDS (such as atazanavir, efavirenz, nevirapine, ritonavir, saquinavir, zidovudine, Norvir®, Reyataz®, Sustiva®), medicine for seizures (such as carbamazepine, hexobarbital, phenytoin, valproate, Depakene®, Dilantin®), medicine to treat impotence (such as sildenafil, tadalafil, vardenafil, Adcirca®, Cialis®, Levitra®, Viagra®), medicine for nerves or sleeping (such as alprazolam, midazolam, triazolam, Xanax®), alfentanil (Alfenta®), bromocriptine (Parlodel®), cilostazol (Pletal®), cyclosporine (Gengraf®, Neoral®, Sandimmune®), methylprednisolone (Medrol®), tacrolimus (Prograf®), or vinblastine (Velban®).
  • Clarithromycin and zidovudine (Retrovir®) should be taken at least 2 hours apart from each other, if you also take zidovudine.

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, myasthenia gravis, diabetes, low magnesium or potassium in the blood, or a history of porphyria (an enzyme problem).
  • Tell your doctor if you have a history of heart rhythm problems such as QT prolongation or a slow heartbeat.
  • Stop using this medicine and tell your doctor right away if you have dark urine or pale stools, nausea, vomiting, loss of appetite, pain in your upper stomach, yellow skin or eyes. These could be symptoms of a serious liver problem.
  • Tell your doctor right away if you have any changes to your heart rhythm. You might feel faint, dizzy, lightheaded, 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.
  • If you have severe diarrhea, ask your doctor before taking any medicine to stop the diarrhea.Diarrhea may occur 2 months or more after you stop using this medicine.
  • Tell your doctor right away if you have blistering, peeling, or loose skin, red skin rash, sores or ulcers on the skin, or fever or chills while you are using this medicine. These could be symptoms of serious allergic reactions.
  • Your doctor will need to check your blood at regular visits while you are using this medicine. Be sure to keep all appointments.
  • Only use this medicine to treat the condition intended by your doctor. This medicine will not treat the flu or the common cold.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, red skin rash
  • Dark-colored urine, pale stools, nausea, vomiting, loss of appetite, or pain in your upper stomach, yellow skin or eyes
  • Fast, slow, pounding, or uneven heartbeat
  • Severe nausea, vomiting, upset stomach, abdominal pain
  • Severe diarrhea that does not stop

If you notice these less serious side effects, talk with your doctor:

  • Bad or unusual taste in your mouth
  • Headache
  • Mild diarrhea

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last Reviewed on 06/12/2013

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission ( URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2013 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

This page was last updated: September 18, 2013

Average rating (0)