Nicotine skin patches have been widely sold as the answer to an addiction to smoking. In the UK, you don't need a prescription to buy them but, in California, they have only become available over the counter in the last five years.
Yet, despite a threefold increase in sales, Californian cancer experts have been disappointed not to see a corresponding rise in the numbers of ex-smokers. Nicotine patches, they reported in a recent survey, 'were not associated with a clinically meaningful long-term improvement in successful cessation'.
However, the pharmaceutical companies who make the patches had their marketing licences granted only because they had produced clinical-trial data showing that the patches were a useful aid to quitting smoking. The question is: why haven't the patches worked in the real world?
The answer has implications for medicine in general. As the cancer experts have gently phrased it, 'The efficacy of pharmaceutical aids observed in clinical trials may not extend to effectiveness in the general population' (JAMA, 2002; 288: 1260-4).