Ribavirin (Copegus / Rebetol / Virazole) is an antiviral drug that is active against a range of viruses. It is an approved and effective treatment for hepatitis C when used in combination with interferon alfa (IntronA / Viraferon / Roferon-A) or peginterferon alfa (Pegasys / PegIntron / ViraferonPeg) in HIV-positive and –negative patients. Ribavirin is a nucleoside analogue that disrupts viral replication. Initially, it was investigated as an anti-HIV treatment but research was halted due to poor results.

The recommended dosage for people under 75kg is two 200mg capsules in the morning and three capsules in the evening. For people over 75kg, three capsules are taken both morning and night. Ribavirin should be taken with food.

Based on current research, treatment is recommended for at least 24 weeks, with an additional 24 weeks of treatment for individuals who had high baseline viral loads or genotype 1, which is associated with a poorer response to treatment. Age, male sex and extent of fibrosis may also be considered in extension of treatment. For details of the effectiveness of ribavirin as a treatment for hepatitis C, see Hepatitis C.

Ribavirin has caused severe birth defects in animal studies and women taking ribavirin are advised to use contraception. It has also caused sperm mutations in animal studies and couples should avoid pregnancy while male partners are taking ribavirin. Pregnancy should be avoided until seven months after completing treatment with ribavirin. Breastfeeding is not recommended during treatment with ribavirin.

Ribavirin is not recommended for use in individuals with severe liver damage or autoimmune hepatitis. A kidney check should be performed before a patient starts ribavirin.

Ribavirin with interferon alfa may cause a range of side-effects including headache, fatigue, muscle ache and fever, as well as flu-like symptoms. The most common side-effect of ribavirin is anaemia, which can be treated with epoetin alfa^[1]. Other side-effects include mood swings, irritability, anxiety, insomnia, abdominal pain, nervousness, breathlessness, rash, hair loss, dry skin, nausea, diarrhoea, loss of appetite, dizziness and weight loss.

Unusual or serious side-effects such as chest pain, persistent cough, changes in heart beat, confusion, depression and blood in the urine should be reported to a doctor immediately.

Ribavirin reduces the concentrations of AZT (zidovudine, Retrovir) and d4T (stavudine, Zerit)^[2]. HIV viral load should be closely monitored if ribavirin is being taken concurrently with AZT or d4T, and a change in treatment considered if viral load rises.

There is preliminary evidence that ribavirin may increase the risk of metabolic side-effects, such as pancreatitis, liver abnormalities, lactic acidosis, glucose intolerance and weight loss, associated with the nucleoside reverse transcriptase inhibitors (NRTIs), particularly ddI (didanosine, Videx / VidexEC) and d4T^{[3][4][5][6][7][8]}. These metabolic side-effects have been attributed to mitochondrial toxicity.

Ribavirin does not interact with any currently available protease inhibitors or non-nucleoside reverse transcriptase inhibitors (NNRTIs).

Despite some promising early studies, ribavirin has been shown to have little or no direct effect against HIV^{[9][10][11][12][13][14][15]}. However, test tube studies and preliminary research in humans has shown that ribavirin can act in a similar way to hydroxycarbamide (Hydrea), increasing the potency and effectiveness of ddI^[16][17]. Although there is little or no interest in further testing ribavirin as a direct treatment for HIV, research into ribavirin in combination with ddI is continuing.