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Use of paracetamol for suicide and non-fatal self-poisoning,

and evaluation of the effects of legislation on paracetamol and aspirin in pack sizes

Following earlier work on the use of paracetamol for suicide and non-fatal self-poisoning (see publications below), we have investigated the effects of the legislation which came into effect during September 1998 to restrict the number of tablets per packet of paracetamol and other non-opiate analgesics. This was due to the rising numbers of paracetamol overdoses and increasing numbers of deaths and liver transplantations due to paracetamol poisoning. Before the legislation packs of 100 tablets could be bought from pharmacies and 24 tablets from non-pharmacy outlets such as supermarkets or petrol stations. There was no limit on the number of packs which could be bought at one time. The legislation restricted pack sizes to 32 tablets from a pharmacy (although more can be sold at the pharmacist's discretion) and 16 tablets from a non-pharmacy outlet.

We have evaluated the impact of the legislation on deaths from self-poisoning, numbers of individuals developing liver damage or requiring liver transplantation due to paracetamol poisoning, and non-fatal self-poisoning. In our first study we assessed the impact in the first year after the legislation. More recently we have evaluated the impact in the 3-4 years following the legislation. Suicide deaths from paracetamol and aspirin fell by 22% in the year after the legislation and this reduction persisted in the next two years. Liver unit admissions and liver transplants for paracetamol induced liver damage were reduced by around 30% in the four years after the legislation. Numbers of paracetamol and aspirin tablets taken in non-fatal overdoses were reduced in the three years after the legislation. Large overdoses fell by 20% for paracetamol and 39% for aspirin in the second and third years after the legislation.

This study was carried out in collaboration with colleagues in Derby and Manchester, representatives of UK Liver Units and the Office for National Statistics. It was funded by South East Region NHSE Research and Development Committee.

We have recently completed an analysis of the longer-term impact of the legislation, which showed that in the 11 years following the legislation there were an estimated 765 fewer suicide and open verdict deaths from paracetamol poisoning, which represented a reduction of 43%. A similar impact was found when accidental poisoning deaths were included, and when a conservative method of analysis was used. This reduction was largely unaltered after controlling for a downward trend in deaths involving other methods of poisoning and also suicides by all methods. BMJ, 346, f403. doi:10.1136/bmj.f403

As part of a National Institute for Health Research (NIHR) programme of research in support of the National Suicide Prevention Strategy for England, we wanted to assess whether the current paracetamol pack size is appropriate, and to find out more about the nature of paracetamol overdoses and the people who take them. We have conducted an interview study with 60 patients who presented to the general hospital in Oxford following overdoses of more than 16 tablets. A paper reporting the results is published in Quarterly Journal of Medicine. Half of all paracetamol overdoses involved >16 tablets. Patients were predominantly young (three-quarters aged 16 - 40 years) and female (58.3%); over half (53.3%) had taken a previous paracetamol overdose. Three-quarters said they wanted to die. Half took the overdose within an hour of first thinking of it, half (53.3%) took tablets already in the home and 58.3% bought tablets specifically for the overdose. Ten people tried to buy more than 32 tablets in one transaction; four succeeded. Most knew that a paracetamol overdose could cause death or permanent damage (88.3%) and harm the liver (80.0%) but 70.0% thought they would lose consciousness. Warnings on packs had little deterrent effect. Media and internet influences were identified. Patients chose paracetamol because it was cheap and easily available.

We have also completed a study comparing the impact of different pack sizes of paracetamol in the United Kingdom and Ireland on intentional overdoses (doi: 10.1186/1471-2458-11-460). This showed that sizes of overdoses did not differ markedly between England and Ireland, in spite of smaller pack sizes in Ireland. Variations in sales policy may have influenced the findings.

Publications:

Hawton, K., Bergen, H., Simkin, S., Dodd, S., Pocock, P., Bernal, W., Gunnell, D. & Kapur, N. (2013). Long term effect of reduced pack sizes of paracetamol on poisoning deaths and liver transplant activity in England and Wales: interrupted time series analyses. BMJ, 346, f403. doi:10.1136/bmj.f403

Simkin, S., Hawton, K., Kapur, N. & Gunnell, D. (2012). What can be done to reduce mortality from paracetamol overdoses? A patient interview study. Quarterly Journal of Medicine, 105, 41-51. doi:10.1093/qjmed/hcr135

Hawton, K., Bergen, H., Simkin, S., Arensman, E., Corcoran, P., Cooper, J., Waters, K., Gunnell, D. & Kapur, N. (2011). Impact of different pack sizes of paracetamol in the United Kingdom and Ireland on intentional overdoses: a comparative study. BMC Public Health, 11, 460. doi: 10.1186/1471-2458-11-460

Hawton K, Simkin S, Deeks J, Cooper J, Johnston A, Waters K, Arundel M, Bernal W, Gunson B, Hudson M, Suri D, Simpson K. (2004) UK legislation on analgesic packs: before and after study of long term effect on poisonings. BMJ, 329, 1076-1079; BMJ,doi:10.1136/bmj.38253.572581.7C.

Hawton, K. (2002) United Kingdom legislation on pack sizes of analgesics: background, rationale, and effects on suicide and deliberate self-harm. Suicide and Life-Threatening Behavior, 32, 223-229.

Hawton, K., Townsend, E., Deeks, J., Appleby, L., Gunnell, D., Bennewith, O., Cooper, J. (2001) Effects of legislation restricting pack sizes of paracetamol and salicylates on self poisoning in the United Kingdom: before and after study BMJ, 322, 1203-1207

Gunnell, D., Murray, V., Hawton, K. (2000) Use of paracetamol (acetaminophen) for suicide and non-fatal poisoning: world-wide patterns of use and misuse. Suicide and Life-Threatening Behavior, 30, 313-320.

Gunnell, D., Hawton, K., Murray, V., Garnier, R., Bismuth, C., Fagg, J., Simkin, S. (1997) Use of paracetamol for suicide and non-fatal poisoning in the UK and France: are restrictions on availability justified? Journal of Epidemiology and Community Health, 51, 175-179.

Hawton, K., Ware, C., Mistry, H., Hewitt, J., Kingsbury, S., Roberts, D., Weitzel, H. (1996) Paracetamol self-poisoning. Characteristics, prevention and harm reduction. British Journal of Psychiatry, 168, 43-48.

Hawton, K., Ware, C., Mistry, H., Hewitt, J., Kingsbury, S., Roberts, D., Weitzel, H. (1995) Why patients choose paracetamol for self poisoning and their knowledge of its dangers. BMJ, 310, 164-164.