Ribavirin Dosing Should be Based on Renal Function Not Body Weight
for Chronic Hepatitis C

DGReview


Ribavirin Dosing Should be Based on Renal Function Not Body Weight
for Chronic Hepatitis C
A DGReview of :"Evidence that plasma concentration rather than dose
per kilogram body weight predicts ribavirin-induced anaemia"
Journal of Viral Hepatitis

02/06/2004
By Mary Beth Nierengarten


For patients with chronic hepatitis C who receiving combination
treatment with interferon and ribavirin, dosing of ribavirin should
be based on renal function instead of body weight, reports a study
from Sweden.

Although ribavirin dosing is currently based on body weight, a more
pharmacological and physiological dosing strategy may be to dose
ribavirin according to renal function. Based on the fact that
ribavirin is eliminated primarily through the kidneys and previously
published data that shows ribavirin plasma concentrations are mainly
determined by the kidneys, the authors of this study hypothesise that
plasma concentrations are probably more closely related to side
effects of ribavirin, particularly anaemia, than body weight.

To test this hypothesis, Karin Lindahl, MD, and colleagues,
Karolinska Institute and Huddinge University Hospital, Stockholm,
prospectively examined 213 ribavirin samples collected from 108
consecutive patients undergoing standard treatment with combination
interferon and ribavirin (initial dose of 800-1200 mg/daily). Plasma
samples were taken 12 hours after dosing at week 4, 8, and 12 of
treatment, and ribavirin plasma concentrations were measured using
high-performance liquid chromatography. Changes in haemoglobin levels
and creatinine concentration were also measured.

Based on 209 evaluable plasma samples, the mean ribavirin
concentration was 8.19 µ (range of 0-17.7 µ). No apparent association
was found between the absolute or relative drop in haemoglobin and
dose of ribavirin per kilogram (kg) of bodyweight, although a trend
was observed in a correlation between ribavirin concentration and
drop in haemoglobin. A dose-response curve showed that a maximal drop
in haemoglobin was achieved at a 4.4 µ concentration of ribavirin.

These data support the hypothesis that a plasma concentration and not
body weight is more strongly associated with ribavirin-induced
anaemia. The authors conclude that ribavirin dosing should be based
on creatinine clearance and not on body weight given that ribavirin
concentrations depend primarily on renal function.


J Viral Hepat 2004 Jan;11:1:84-87. "Evidence that plasma
concentration rather than dose per kilogram body weight predicts
ribavirin-induced anaemia"