ribavirin

Ribavirin is an antiviral drug. It is used in combination with interferon for the treatment of chronic hepatitis C. Although the exact mechanism of its action is unknown, it is thought to interfere with the production and/or action of viral DNA and RNA which are critical to the survival and multiplication of the virus. Ribavirin was approved by the FDA in December 1998.

What brand names are available for ribavirin?

Rebetol, Copegus, Ribasphere, RibaPak, Moderiba

Do I need a prescription for ribavirin?

Yes

The most common side effect seen with the combination of ribavirin and interferon is a flu-like syndrome consisting of:

• body aches and pains,
• fever,
• chills,
• headache, and
• malaise.

Other possible side effects that may occur during therapy with ribavirin and interferon are:

• fatigue,
• weakness,
• nausea,
• anorexia,
• heartburn,
• insomnia,
• irritability,
• difficulty breathing,
• rash,
• itching, and
• alterations in taste perception.

The most serious side effect seen with ribavirin is anemia. Careful consideration is advised if ribavirin is used in patients with heart or circulation problems since the anemia may aggravate these conditions.

Ribavirin should be avoided among patients who have severe kidney disease and have lost most of their kidneys' function.

Therapy with ribavirin and interferon may aggravate psychiatric conditions or may trigger a psychiatric condition such as depression, psychosis, aggressive behavior, hallucinations, or violent behavior. Patients should be closely monitored for the development of these psychiatric conditions.

Therapy with ribavirin and interferon has caused abnormalities of the thyroid gland. If these abnormalities persist and cannot be controlled by medication, it may be necessary to discontinue therapy.

• Ribavirin dosing is individualized based upon a patient's weight and previous use of interferon.
• Dosing also depends on the formulation used and the type of hepatitis C virus infection.
• The recommended dose of ribavirin tablets is 800 to 1200 mg divided every 12 hours for 24 to 48 weeks.
• Ribavirin may be taken with or without food. When taken orally, it should be taken consistently. For example, it should be taken at the same time or times each day and with or without food each time.

Ribavirin used at the same time as other antiviral drugs with similar mechanisms of action may cause a condition in which lactic acid accumulates in the blood (lactic acidosis) which can lead to serious medical problems. Other such antiviral drugs include those used to manage HIV infection, for example, zidovudine (Retrovir), zalcitabine (Hivid) or stavudine (Zerit).

Adding ribavirin treatment among patients taking azathioprine (Imuran, Azasan) increases the chance of severe pancytopenia (a reduction in the numbers of all types of blood cells) due to azathioprine. This occurs because ribavirin reduces the breakdown of a harmful chemical produced during the breakdown of azathioprine.

There are no studies of ribavirin in pregnant women; however, in pregnant animals receiving ribavirin in smaller doses than those given to humans there have been fetal birth defects and death. Therefore, ribavirin should not be taken by pregnant women. In addition, women who are receiving ribavirin therapy should wait at least 6 months after ribavirin is stopped before becoming pregnant in order to prevent potential effects of ribavirin on the fetus.

Since ribavirin may cause abnormalities in sperm, men taking ribavirin should avoid attempts to impregnate sexual partners and should wait six months after discontinuing the drug before attempting to impregnate.

Although it is unknown if ribavirin is excreted in human milk during lactation, studies in animals have shown interferons to be excreted into milk, and the potential exists for serious adverse effects from combination therapy. Therefore, breastfeeding should be discontinued during treatment.

What preparations of ribavirin are available?

Capsule: 200 mg.

How should I keep ribavirin stored?

Ribavirin should be refrigerated at 2 C to 8 C (36 F to 46 F).