Drug research leaves Astra with a headache

British drug giant AstraZeneca was today suffering the ill effects of medical research that criticised Seroquel, a schizophrenia medicine that is the pharma firm's second best-selling product.

Finnish scientists reporting in the medical journal The Lancet said that Swiss rival Novartis's Clozaril drug leaves patients with a significantly lower risk of suicide than those taking Astra's Seroquel.

Newer drugs like Seroquel had been seen as safer due to fewer side effects, but today's research threatens to change that view. The researchers concluded that restrictions on older drugs, which had been reserved for use as a last resort, should be reassessed.

It will come as a blow to Astra, which raked in $4.45 billion (£2.76 billion) from sales of Seroquel last year. In the US, Seroquel is also facing a large number of lawsuits, with patients claiming the antipsychotic drug led to the development of diabetes.

Shares in AstraZeneca today fell 4p to 2650½p.