Drug regulators and, indeed, pharmaceutical companies themselves often reassure themselves that the patient knows about the risks of the drug he is taking because of the packet insert provided each time. Small print, perhaps, but it's all there if you have the mind, and a magnifying glass, to read it.
But is the whole truth printed on the inserts? Doubts have been raised following a review of a new class of drugs called thiazolidinediones, designed to treat type II diabetes. Rezulin (troglitazone) is one of the first to be licensed both in the UK and the USA.
One study, carried out by the Institute of Molecular and Cellular Genetics and Biology in Illkirch, France, found that 2 per cent of patients suffer hepatic dysfunction, which can lead to liver failure, a potentially lethal side effect not noted by the drug company (Lancet, 2000; 355: 1008-10).
Not surprising, really, says Sidney Wolfe of the Public Citizen's Health Research Group. Only one of 11 efficacy studies for two other thiazolidinediones submitted to the US Food and Drug Administration as part of the approval packages has been published (Lancet, 2000; 356: 254).
His own research into FDA data sources has also discovered that thiazolidinediones can lead to cardiac failure, "a serious finding not previously adequately acknowledged in the product labelling or on the company websites," he states.
Reactions that the drug company does accept include infections, headache, pain, dizziness, nausea, rhinitis, diarrhoea and urinary tract infections.
Less common has been jaundice, but this was reversed once the patients were taken off the drug. Even without liver and cardiac failure, perhaps even the small print that is published might give a potential patient pause.