Telaprevir is an antiviral agent. Specifically, it belongs to the class of medications known as protease inhibitors. Protease is an enzyme that is needed by viruses for reproduction. Telaprevir blocks the action of protease, slowing the growth of the virus.

This medication is used in combination with peginterferon alfa and ribavirin, to treat chronic (long-term) hepatitis C for people who have not been treated before, or who have been treated with interferons and not responded well.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. 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 usual adult dose of telaprevir is 1,125 mg (three 375 mg tablets) taken 2 times a day. Each dose should be taken no less than 10 hours and no more than 14 hours apart. Telaprevir should be taken with high-fat food. Swallow the tablets whole, do not crush, break, or chew them.

It is important that the dose is not reduced, as this may cause the treatment to fail. The recommended length of treatment with telaprevir is 12 weeks. Telaprevir must be taken in combination with peginterferon alfa and ribavirin. The other two medications will be continued for a longer period of time after treatment with telaprevir is completed.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, and it is within 6 hours of that dose, take it as soon as possible with food, and continue with your regular schedule. If it is more than 6 hours since you missed a dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice. If you miss more than one dose, call your doctor immediately.

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

Each purple, film-coated, capsule-shaped tablet, debossed with "V 375" on one side, contains telaprevir 375 mg. Nonmedicinal ingredients: colloidal silicon dioxide, croscarmellose sodium, D&C Red No. 40, dibasic calcium phosphate (anhydrous), FD&C Blue No. 2, hypromellose acetate succinate, microcrystalline cellulose, polyethylene glycol, polyvinyl alcohol, sodium lauryl sulfate, sodium stearyl fumarate, talc, and titanium dioxide.

Do not take telaprevir if you:

• are allergic to telaprevir or any ingredients of the medication
• are pregnant or your female partner is pregnant
• are unable to take peginterferon alfa or ribavirin
• are taking any of the following medications:
• alfuzosin
• amiodarone
• carbamazepine
• cisapride
• eplerenone
• ergot derivatives (e.g., dihydroergotamine, ergotamine)
• flecainide
• pimozide
• propafenone
• quinidine
• rifampin
• sildenafil
• "statin" cholesterol-lowering medications (e.g., atorvastatin, lovastatin, simvastatin)
• St. John's wort
• triazolam
• "triptan" medications (e.g., eletriptan)
• vardenafil

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.

• burning or itching around the anus
• change in taste sensation
• diarrhea
• hemorrhoids
• itchiness
• nausea
• vomiting

Although most of the 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:

• fainting
• mild to moderate rash
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)

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

• signs of a severe skin reaction such as blistering, peeling, ulcers, rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever
• skin rash that gets worse

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.

Abnormal heart rhythms: This medication can cause abnormal heart rhythms. Certain medications (e.g., sotalol, quinidine, thioridazine, chlorpromazine, droperidol, pimozide, gatifloxacin, moxifloxacin, mefloquine, pentamidine, dolasetron, tacrolimus) can increase the risk of a type of an abnormal heart rhythm called QT prolongation, and should not be used in combination with telaprevir. You are more at risk for this type of abnormal heart rhythm and its complications if you:

• are female
• are older than 65 years of age
• have a family history of sudden cardiac death
• have a history of heart disease or abnormal heart rhythms
• have a slow heart rate
• have congenital prolongation of the QT interval
• have diabetes
• have had a stroke
• have low potassium, magnesium, or calcium levels
• have nutritional deficiencies

If you have heart disease, an abnormal heart rhythm, or are taking certain medications that may increase your risk of QT prolongation, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Anemia: Telaprevir may cause low levels of red blood cells, a condition called anemia. If you experience symptoms of anemia, such as dizziness, shortness of breath, feeling unusually tired, or pale skin, contact your doctor as soon as possible.

Your doctor will do blood tests regularly to monitor the number of specific types of blood cells, including red blood cells, in your blood.

Birth Control: Telaprevir must be used with ribavirin and peginterferon alfa. Treatment with ribavirin can cause severe birth defects to an unborn child. Both partners should use a reliable form of birth control while taking this medication and for 6 months afterwards (the time it takes for ribavirin to be cleared from the body). For women, your doctor will not give you telaprevir until you have had a negative pregnancy test. Your doctor should have you continue to do monthly pregnancy tests to ensure that you do not become pregnant while using this medication.

Methods of birth control that use hormones, such as a birth control pill, patch or injection, may not be fully reliable as telaprevir interacts with many medications and may change the way that your body uses the hormones. At least 2 forms of non-hormonal birth control (condom, diaphragm) must be used while you are taking this medication.

Infection with HIV or hepatitis B: The safety and effectiveness of treatment with telaprevir have not been established for people who also have human immunodeficiency virus (HIV) or hepatitis B virus (HBV).

Kidney function: The safety and effectiveness of using telaprevir have not been established for people with severely reduced kidney function. If you have decreased kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Telaprevir is not recommended for people with active, worsening liver disease, or moderate to severely reduced liver function. If you have a history of reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Organ Transplantation: The safety and effectiveness of treatment with telaprevir have not been established for people with liver or other organ transplants. Telaprevir may interact with medications used to prevent rejection of the transplanted organ.

Skin reactions: Telaprevir may cause skin rash or itchiness with or without a rash. Rarely, people taking telaprevir experience a severe skin reaction that can be life-threatening. If you experience mouth sores or ulcers, red or inflamed eyes (such as "pink eye"), a rash that gets worse, or develops into blisters, covers a large area of the body, or is associated with a fever, get immediate medical attention.

Pregnancy: Telaprevir has not been studied for use by pregnant women and it must be taken with peginterferon alfa and ribavirin. Ribavirin has been shown to cause serious problems in the developing fetus. As a result, telaprevir (plus peginterferon alfa and ribavirin) should not be used by pregnant women or by men whose partners are pregnant. Both partners should use a reliable form of birth control while taking this medication and for 6 months afterwards. Tell your doctor immediately if you become pregnant while using this medication.

Breast-feeding: It is not known if telaprevir 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 and adolescents: The safety and effectiveness of using this medication have not been established for children and adolescents less than 18 years of age.

Seniors: Seniors may be more likely to experience side effects when taking telaprevir.

There may be an interaction between telaprevir 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.