Telithromycin belongs to the family of medications known as ketolide antibiotics. It is used to treat pneumonia caused by certain bacteria. It works by killing or stopping the growth of bacteria.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended adult dose of telithromycin is 800 mg (2 of the 400 mg tablets) once daily, taken with or without meals for 7 to 10 days.

Taking this medication at bedtime helps to avoid potential side effects such as vision changes and fainting.

Do not chew or crush the tablets. Swallow the tablets whole with a glass of water, as this medication has a bitter taste.

Telithromycin must be taken for the recommended duration of treatment, even if you are feeling better. This will ensure that the bacteria causing the infection are killed and cannot grow back.

It is important to take this medication exactly as prescribed by your doctor. Take this medication at the same time each day. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take more than one dose of this medication in a 24-hour period. Do not take a double dose to make up for a missed dose. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from heat and light, and keep it out of the reach of children.

Telithromycin should not be taken by anyone who:

• is allergic to telithromycin or to any of the ingredients of the medication
• is allergic to macrolide antibiotics (e.g., erythromycin, clarithromycin, azithromycin)
• is taking astemizole, cisapride, pimozide, terfenadine, or ergot alkaloids (e.g., ergotamine, dihydroergotamine, methysergide)
• has a history of hepatitis or jaundice (yellowing of the skin or whites of the eyes) associated with taking telithromycin or any macrolide antibiotic (e.g., erythromycin, clarithromycin, azithromycin)
• has myasthenia gravis

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abnormal dreams
• dizziness
• gas
• headache
• indigestion
• mild diarrhea
• nausea
• stomach pain
• taste disturbances
• vomiting

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• confusion
• fainting
• hallucinations (seeing or hearing things that aren't really there)
• irregular heartbeat
• symptoms of liver problems (e.g., nausea, loss of appetite, yellow of the skin and eyes, abdominal pain, dark urine)
• vision problems (e.g., blurred vision, double vision, trouble focusing)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• muscle weakness, pain, breathing difficulties
• severe allergic reactions (e.g., hives; difficulty breathing or swallowing; itching; rash; red spots; blisters; swelling of the hands, mouth, or throat)
• severe diarrhea

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Antibiotic-associated colitis: This medication, like other antibiotics, may cause a potentially dangerous condition called antibiotic-associated or pseudomembranous colitis. Symptoms include severe, watery diarrhea that may be bloody. If you notice these symptoms, stop taking telithromycin and contact your doctor as soon as possible.

Fainting: This medication may cause fainting, especially in people who are experiencing severe nausea, vomiting, or lightheadedness. If these symptoms occur, avoid driving, operating machinery, or participating in hazardous activities while taking telithromycin. If you faint, stop taking telithromycin and contact your doctor immediately.

Heart conditions: Telithromycin can cause an abnormal heart rhythm and should be avoided by people with certain heart rhythm problems, especially long QT syndrome, congenital QT interval prolongation, and bradycardia (low heart rate). People who have had irregular heart rhythms caused by other medications in the past should avoid taking telithromycin. It should also be avoided by people with low blood potassium or magnesium levels, and by people taking certain medications used to treat irregular heart rhythms (e.g., quinidine, procainamide, amiodarone, sotalol). If you experience an irregular heartbeat, stop taking this medication and contact your doctor.

Kidney problems: People with reduced kidney function should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. People with severely reduced kidney function may require lower doses of telithromycin.

Liver problems: Although rare, this medication can cause severe liver problems. If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, stop taking telithromycin and contact your doctor immediately.

People with reduced liver function should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Vision changes: Telithromycin may cause blurred vision, difficulty focusing, and double vision. These vision changes are usually mild to moderate and usually occur after the first or second dose. They may last for a few hours, may recur, and usually disappear when treatment is finished. People taking telithromycin should be aware of how this medication affects them before driving a vehicle or operating machinery. If vision changes occur, stop taking telithromycin and contact your doctor. Your doctor may suggest taking telithromycin at bedtime.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if telithromycin passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 13 years of age.

There may be an interaction between telithromycin and any of the following:

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.