United States of America. The Food and Drug Administration has approved rosiglitazone (Avandia: SmithKline Beecham), a new thiazolidinedione drug, to treat type II or adult-onset diabetes in patients who are not taking insulin, in conjunction with dietary measures to control weight. Rosiglitazone improves a condition believed to be an important underlying cause of adult-onset diabetes: resistance of the body to insulin.

Adverse events commonly reported with rosiglitazone included infection, pain and headache, but at rates comparable to those found in placebo-treated patients. Mild to moderate oedema, an increase in blood cholesterol and anaemia were also reported in patients treated with rosiglitazone, but did not usually require discontinuation of treatment.

Another drug of the thiazolidinedione class, troglitazone (Rezulin: Parke-Davis), has been associated with idiosyncratic hepatotoxicity or liver failure. This may occur at any time during treatment with troglitazone, and has led to liver transplants or death. In clinical studies of patients treated with rosiglitazone, there was no evidence of drug- induced hepatotoxicity.

Nevertheless, because of the liver toxicity associated with troglitazone, the FDA is recommending that liver enzymes should be checked at the start of rosiglitazone therapy and quarterly during the first year. After the first year, testing should continue periodically.

Reference: FDA Talk Paper T99-25 dated 26 May 1999.