Telithromycin (By mouth)


Telithromycin (tel-ith-roe-MYE-sin)

Treats pneumonia (a lung infection) that is caused by bacteria. This medicine is an antibiotic.

Brand Name(s)

Ketek, Ketek Pak

When This Medicine Should Not Be Used

How to Use This Medicine


  • Take your medicine as directed.
  • You may take this medicine with or without food.
  • It is best to take this medicine once a day at the same time everyday.
  • Swallow the tablet whole. Do not crush, break, or chew it.
  • Take all of the medicine in your prescription to clear up your infection, even if you feel better after the first few doses.
  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose. Do not take more than one dose in 24 hours.

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.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. 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.

  • Make sure your doctor knows if you are using cyclosporine (Gengraf®, Neoral®, Sandimmune®), digoxin (Lanoxin®), metoprolol (Lopressor®, Toprol®), rifampin (Rifadin®, Rimactane®), sirolimus (Rapamune®), sotalol (Betapace®), tacrolimus (Prograf®, Protopic®), theophylline (Theo-24®), or a diuretic ("water pill") such as furosemide, hydrochlorothiazide, or Lasix®. Tell your doctor if you are also using medicines to lower your cholesterol (such as atorvastatin, lovastatin, simvastatin, Advicor®, Caduet®, Lipitor®, Mevacor®, or Zocor®), sedatives or medicines to treat seizures (such as carbamazepine, hexobarbital, phenobarbital, phenytoin, midazolam, triazolam, Dilantin®, Halcion®, Versed®, or Tegretol®), ergot medicines (such as dihydroergotamine, ergotamine, Cafergot®, D.H.E.® 45, Ergomar®, Ergostat®, or Migranal®), medicines to treat fungal infections (such as itraconazole, ketoconazole, Nizoral®, or Sporanox®), blood pressure medicine (such as amlodipine, diltiazem, verapamil, Calan®, Cardizem®, Isoptin®, Norvasc®, or Verelan®), medicines for heart rhythm problems (such as dofetilide, procainamide, quinidine, Cardioquin®, Procanbid®, Pronestyl®, Quinaglute®, or Tikosyn®), or a blood thinner (such as warfarin, Coumadin®).

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant, planning to become pregnant, or breastfeeding. Tell your doctor if you have kidney disease, liver disease, certain heart problems (such as QTc prolongation), a slow heartbeat, or low potassium or magnesium levels in your blood.
  • You might feel faint or have trouble seeing after you take this medicine. This is more common after the first or second dose. You might have blurred vision, double vision, or trouble focusing, especially when you change from looking far away to looking up close. These symptoms might last for several hours after you take your dose and may come back with the next dose. Avoid driving, using machines, or doing anything else that could be dangerous if you feel like fainting or if you cannot see well. Talk to your doctor if you feel faint or have trouble seeing when you take this medicine.
  • Stop using this medicine and call your doctor right away if you have any symptoms of liver disease. This may include severe stomach pain, unusual tiredness or weakness, loss of appetite, nausea, yellow skin or eyes, or clay-colored stools.
  • Do not take this medicine for any other infection. You should only use it for pneumonia if your doctor tells you to.
  • This medicine may cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you stop taking this medicine. Do not take any medicine to treat diarrhea without first checking with your doctor. If you have any questions or if mild diarrhea continues or gets worse, check with your doctor.
  • Call your doctor if your symptoms do not improve or if they get worse.
  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments. Blood tests may be needed to check for unwanted effects.

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
  • Blurred vision or other vision problems.
  • Dark-colored urine or pale stools.
  • Fainting spells, or lightheadedness.
  • Fast or uneven heartbeat.
  • Muscle cramps.
  • Nausea, vomiting, loss of appetite, or severe pain in your upper stomach.
  • Severe diarrhea (watery and may be bloody).
  • Skin rash or itching.
  • Yellowing of your skin or the whites of your eyes.

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

  • Dizziness.
  • Headache.
  • Mild diarrhea.
  • Tiredness or body aches.

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 8/4/2014

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.