A Cochrane review included 2 studies with a total of 293 subjects. Only one of the trials was regarded as having low bias risk. Azathioprine did not significantly decrease mortality (RR 0.80, 95% CI 0.49 to 1.31, 2 trials). Azathioprine did not improve pruritus at one-year intervention (RR 0.71, 95% CI 0.28 to 1.84, 1 trial), cirrhosis development, or quality of life. Patients given azathioprine experienced significantly more adverse events than patients given no intervention or placebo (RR 2.44, 95% CI 1.14 to 5.20, 2 trials). The common adverse events were rash, severe diarrhoea, and bone marrow depression.
Comment: The quality of evidence is downgraded by imprecise results (few patients and wide confidence intervals).