Ribavirin is a nucleoside analogue.
Ribavirin has a broad spectrum of virustatic activity against both DNA and RNA viruses.
The precise mechanism of action of ribavirin is unknown.
The development of resistance to ribavirin is rare. However, mutations leading to resistance of hepatitis C virus have been reported.
Reduction of hepatitis C plasma viral load to undetectable levels by 24 weeks of therapy correlates with sustained virologic response (SVR). Patients who have not attained this benchmark are not likely to achieve SVR (less than 2% will do so) and thus should stop therapy.
Ribavirin is well absorbed after oral administration. However, pre-systemic drug elimination limits absolute bioavailability to 33 to 65%. The mean apparent volume of distribution (Vd) ranges from 800 to 2000 liters, indicating extensive tissue distribution. There is no significant plasma protein binding of ribavirin. Ribavirin undergoes reversible phosphorylation and also degradation via deribosylation and amide hydrolysis. The estimated renal clearance is approximately 40% and renal tubular secretion appears to play a role.
The most important adverse effect is anemia from ribavirin-induced hemolysis. This may accompanied by hyperuricemia and hyperbilirubinemia.
Oral Solution 40mg/ml
Powder for Inhalation Solution 6g
See text for specific dosing
The manufacturer does not recommend administration to patients with creatinine clearances of less than 50 mL/min.
No specific guidelines are available
Ribavirin monotherapy is not effective for the treatment of hepatitis C and should be combined with interferon alfa-2b.
Ribavirin is not a substrate and does not affect the CYP450 enzyme system.
Category X: Drug contraindicated.
CBC with differential, hemoglobin/hematocrit, LFTs, pregnancy testing, thyroid function tests (TFTs)
Copegus®/Hoffmann La Roche Inc
Ribasphere®/Par Pharmaceutical Inc, Three Rivers Pharmaceuticals, LLC
Ribavirin/Teva Pharmaceuticals USA Inc, Sandoz Pharmaceuticals, Warrick Pharmaceuticals Corp