Smaller packs of paracetamol have reduced overdose deaths by 43%

'Paracetamol overdoses result in some 100 to 200 deaths per year. While it is not the most common method of suicide, it is an important one in that deaths often result from impulsive acts where death may not be intended,' says lead researcher Professor Keith Hawton of the Centre for Suicide Research at Oxford.

'We have estimated that there have been 600 fewer deaths due to paracetamol overdose than would have been expected based on trends before the legislation was introduced' he adds. 'While some of this effect could have been due to improved hospital management of paracetamol overdoses we believe that this has in large part been due to the introduction of the legislation. For example, we found that following the legislation coming into force the average size of overdoses declined.'

Paracetamol overdoses are a common method of suicide and frequent cause of liver damage.

In September 1998, new legislation was introduced by the UK Government which limited packs of paracetamol bought in pharmacies to a maximum of 32 tablets, and 16 tablets for packs bought elsewhere.

Professor Hawton's work provided much of the evidence that led to the change in legislation. 'During the 1990s we drew attention to the size of the problem of paracetamol overdoses in England and showed that this had increased as paracetamol sales rose,' he explains. 'We also highlighted the fact that in France, where smaller packs were on sale, deaths due to paracetamol overdose appeared to be far fewer.  

'We also conducted research during the 1990s which showed that many people who take paracetamol overdoses do so impulsively and use tablets available in the household. This was an important factor which influenced the regulatory agency to introduce this particular legislation.'

In this study, the UK research team investigated the long-term impact of the legislation on poisoning deaths (especially suicides) in England and Wales, and on the number of patients admitted to hospital for liver failure.

The group found a significant decrease in deaths involving paracetamol. The estimated average decrease in the number of deaths was 17 per quarter compared with the expected number based on what was happening during the pre-intervention period. This resulted in an overall decrease of 43% in the number of deaths in the 11 year post-legislation period.

The number of registrations at UK liver units for paracetamol-induced liver transplantation in England and Wales following the legislation was 482 fewer than expected: a 61% reduction.

Data on poisoning deaths were examined between 1993 and 2009 and liver unit registrations between 1995 and 2009. Data were taken from the Office of National Statistics for individuals aged 10 years and over (paracetamol poisoning in children younger than 10 years is usually accidental). Data on liver transplants were supplied by UK Transplant (now NHS Blood and Transplant).

The researchers say that benefits should not lead to complacency, as there continues to be an average of 121 deaths each year due to paracetamol poisoning.

Professor Hawton says: 'While suicide is a complex phenomenon requiring a range of strategies to achieve meaningful prevention, the relative success of restricting pack sizes of paracetamol shows that even simple approaches like this can help prevent some deaths, especially those where people take overdoses on impulse which they might later regret.'