Effect of withdrawal of co-proxamol on prescribing and deaths from drug poisoning in England and Wales: time series analysisBMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b2270 (Published 18 June 2009) Cite this as: BMJ 2009;338:b2270
- Keith Hawton, professor of psychiatry and director1,
- Helen Bergen, researcher1,
- Sue Simkin, researcher1,
- Anita Brock, senior research officer2,
- Clare Griffiths, principal research officer2,
- Ester Romeri, research officer2,
- Karen L Smith, senior medical statistician3,
- Navneet Kapur, professor and honorary consultant in psychiatry, head of research4,
- David Gunnell, professor of epidemiology5
- 1Centre for Suicide Research, University of Oxford Department of Psychiatry, Warneford Hospital, Headington, Oxford OX3 7JX
- 2Office for National Statistics, London EC1R 1UW
- 3Centre for Statistics in Medicine, Wolfson College Annexe, University of Oxford, Oxford, OX2 6UD
- 4Centre for Suicide Prevention, University of Manchester, Manchester M13 9PL
- 5Department of Social Medicine, University of Bristol, Bristol BS8 2PR
- Correspondence to: K Hawton
- Accepted 11 March 2009
Objective To assess the effect of the UK Committee on Safety of Medicines’ announcement in January 2005 of withdrawal of co-proxamol on analgesic prescribing and poisoning mortality.
Design Interrupted time series analysis for 1998-2007.
Setting England and Wales.
Data sources Prescribing data from the prescription statistics department of the Information Centre for Health and Social Care (England) and the Prescribing Services Unit, Health Solutions Wales (Wales). Mortality data from the Office for National Statistics.
Main outcome measures Prescriptions. Deaths from drug poisoning (suicides, open verdicts, accidental poisonings) involving single analgesics.
Results A steep reduction in prescribing of co-proxamol occurred in the post-intervention period 2005-7, such that number of prescriptions fell by an average of 859 (95% confidence interval 653 to 1065) thousand per quarter, equating to an overall decrease of about 59%. Prescribing of some other analgesics (co-codamol, paracetamol, co-dydramol, and codeine) increased significantly during this time. These changes were associated with a major reduction in deaths involving co-proxamol compared with the expected number of deaths (an estimated 295 fewer suicides and 349 fewer deaths including accidental poisonings), but no statistical evidence for an increase in deaths involving either other analgesics or other drugs.
Conclusions Major changes in prescribing after the announcement of the withdrawal of co-proxamol have had a marked beneficial effect on poisoning mortality involving this drug, with little evidence of substitution of suicide method related to increased prescribing of other analgesics.
We thank Doug Altman of the Centre for Statistics in Medicine, University of Oxford, for statistical advice, and staff at the Information Centre for Health and Social Care (England) and Prescribing Services Unit, Health Solutions Wales, for providing prescription data.
Contributors: KH and SS had the idea for the study. KH, DG, and NK obtained funding. KH, HB, SS, AB, and CG designed the study. AB and ER extracted mortality data. KS provided expert statistical advice. HB conducted the statistical analysis. All authors participated in writing of the manuscript. KH is guarantor.
Funding: This work was funded by a National Institute of Health Research (NIHR) Programme Grant for Applied Research (RP-PG-0606-1247). The views and opinions expressed in this paper do not necessarily reflect those of the Department of Health/NIHR or NHS. The funders played no role in the analysis or write up of this paper. KH is also supported by Oxfordshire and Buckinghamshire Mental Health NHS Foundation Trust and HB by the Department of Health.
Competing interests: KH and SS presented evidence to the MHRA committee that evaluated co-proxamol.
Ethical approval: None required.
Provenance and peer review: Not commissioned; externally peer reviewed.
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