Fatal poisonings involving paracetamol (acetaminophen) fell after a law introduced in the UK restricted the number of tablets that could be sold across the counter.
But new research has concluded that this reduction may not have been a result of the change in the law. The study, by Oliver Morgan and colleagues from the Department of Primary Care and Social Medicine, Imperial College London, United Kingdom and the UK Office for National Statistics, is published in the latest issue of PLoS Medicine.
Paracetamol is a cheap and effective pain-killer but overdoses (accidental or deliberate) can be fatal. Many suicide attempts involve paracetamol and it is the commonest cause of acute liver failure in many countries. In the UK, since 1998, pharmacies have not been permitted to sell packs of paracetamol containing more than 32 tablet, and other shops cannot sell packs with more than 16 tablets. Using data from the UK Office for National Statistics, the researchers established that, in England and Wales, the average number of deaths in the five years preceding the regulation was 212/year and in the following five years it fell to an average of 154/year. However, in addition, they found that the number of deaths per year involving any drug, and also "non-drug" suicides , fell during the same period of time. When comparing the trends for paracetamol deaths with other poisoning or suicide deaths, the researchers did not find any statistical evidence that the fall in paracetamol deaths was any different to the overall decline in poisoning or suicide death rates in England and Wales.
The implications of the study are further discussed, in the same issue of PLoS Medicine, by a toxicologist, Professor Nick Buckley (Australian National University Medical School) and David Buckley (University of Bristol, UK). In their view, "It seems most likely that the pack size regulations did change the pattern of paracetamol poisoning but that changes were far more modest than hoped." Like the authors of the research, they say it is important that, whenever public health legislation is introduced, the impact should be properly evaluated.