Troglitazone is a new anti diabetic drug that has already come to the attention of researchers, following early reports that it can cause liver damage.

The drug won approval just a year ago. It is an early example of a thiazolidinedione, a family of drugs that may reduce the need for insulin. Now 600,000 Americans and 200,000 Japanese take it regularly.

Early feedback from doctors indicated it was successful in reducing hyperglycaemia (high blood sugar) in patients with type II diabetes. But isolated reports were also suggesting that it could cause liver dysfunction even liver failure, in a few patients. Several deaths from complete liver failure have already been reported.

A review of US trials which involved 2,510 patients found that 48 of them 1.9 per cent had liver dysfunction, compared with three people given a placebo.

In addition, according to Physicians' Desk Reference, the US drug "bible", 20 people were withdrawn from the initial trials because of liver problems.

But, as they say, the jury's still out. Dr Hiroo Umura from Kyoto University, who assessed the review, said the drug should be given only to patients who can be monitored frequently, at least until the severity of liver dysfunction caused by the drug becomes clearer (New Eng J Med, 1998; 338: 908-9).

Dr Paul Watkins of the University of Michigan Medical Centre states, in the same issue, that on this basis, around 2 per cent of patients should be taken off the drug.

Several cases of jaundice have also been reported, but the drug otherwise seemed well tolerated. Other reactions included infections, headache and general pain, although at levels no higher than those suffered by the placebo group.