Objective: To examine inhospital mortality and morbidity associated with self-poisoning with different drug classes over an extended period.
Design, setting and participants: A prospective cohort study over 26 years (1987–2012) with limited follow-up of patients presenting consecutively to a primary and tertiary referral toxicology centre covering Newcastle, Lake Macquarie and Port Stephens, Australia.
Main outcome measures: Hospital length of stay, types of drugs ingested, intensive care unit (ICU) admission, requirement for ventilation, inhospital deaths and rates of antidepressant drug use in Australia.
Results: Over the study period, there were 17 266 admissions of patients poisoned by 34 342 substances (16 723 drugs available only on prescription). The median length of stay was 16 hours, 12.2% of patients (2101/17 266) were admitted to an ICU, 7.4% (1281/17 266) were ventilated and 78 (0.45%) died in hospital. Patient demographics, social and psychiatric factors remained stable over the 26-year period, but case fatality decreased (from 0.77% [15/1955] to 0.17% [7/4060]) as did ICU admissions (19.2% [376/1955] to 6.9% [280/4060]), ventilation (13.7% [268/1955] to 4.8% [193/4060]) and LOS. The most frequently ingested substances were alcohol, benzodiazepines, paracetamol, antidepressants and antipsychotics. There was a substantial fall in some highly toxic drugs (tricyclic antidepressants, barbiturates, conventional antipsychotics and theophylline), but increases in less toxic selective serotonin reuptake inhibitors, serotonin–noradrenaline reuptake inhibitors and paracetamol. A greater than sixfold increase in community antidepressant use was accompanied by only minor changes in overall and antidepressant self-poisoning rates.
Conclusion: Over two decades, there were decreases in poisonings by many highly toxic drugs which were associated with substantial reductions in morbidity and inhospital deaths. Despite massive increases in the number of antidepressant prescriptions, neither rates of self-harm nor the proportion of antidepressant poisonings increased markedly.
- 1. Australian Bureau of Statistics. Causes of death, Australia, 2012. Canberra: ABS, 2014. (ABS Cat. No. 3303.0.)
- 2. Australian Institute of Health and Welfare. Suicide and hospitalised self-harm in Australia: trends and analysis. Injury research and statistics series No. 93. Canberra: AIHW, 2014. (AIHW Cat. No. INJCAT 169.) http://www.aihw.gov.au/publication-detail/?id=60129549729 (accessed Apr 2015).
- 3. Martin G, Swannell SV, Hazell PL, et al. Self-injury in Australia: a community survey. Med J Aust 2010; 193: 506-510. <MJA full text>
- 4. Roberts DM, Karunarathna A, Buckley NA, et al. Influence of pesticide regulation on acute poisoning deaths in Sri Lanka. Bull World Health Organ 2003; 81: 789-798.
- 5. Carlsten A, Allebeck P, Brandt L. Are suicide rates in Sweden associated with changes in the prescribing of medicines? Acta Psychiatr Scand 1996; 94: 94-100.
- 6. Mant A, Rendle VA, Hall WD, et al. Making new choices about antidepressants in Australia: the long view 1975–2002. Med J Aust 2004; 181 (7 Suppl): S21-S24.
- 7. Hollingworth SA, Burgess PM, Whiteford HA. Affective and anxiety disorders: prevalence, treatment and antidepressant medication use. Aust N Z J Psychiatry 2010; 44: 513-519.
- 8. Baune B, Hay P. Suicide rates and antidepressant prescribing: a casual or causal relationship? PLOS Med 2006; 3: e220.
- 9. Healy D. Did regulators fail over selective serotonin reuptake inhibitors? BMJ 2006; 333: 92-95.
- 10. Buckley NA, Whyte IM, Dawson AH. Cardiotoxicity more common in thioridazine overdose than with other neuroleptics. J Toxicol Clin Toxicol 1995; 33: 199-204.
- 11. Buckley NA, Whyte IM, Dawson AH, et al. Correlations between prescriptions and drugs taken in self-poisoning. Implications for prescribers and drug regulation. Med J Aust 1995; 162: 194-197.
- 12. Buckley NA, Dawson AH, Whyte IM, O'Connell DL. Relative toxicity of benzodiazepines in overdose. BMJ 1995; 310: 219-221.
- 13. Buckley NA, Dawson AH, Whyte IM, Henry DA. Greater toxicity in overdose of dothiepin than of other tricyclic antidepressants. Lancet 1994; 343: 159-162.
- 14. Isbister GK, Bowe SJ, Dawson A, Whyte IM. Relative toxicity of selective serotonin reuptake inhibitors (SSRIs) in overdose. J Toxicol Clin Toxicol 2004; 42: 277-285.
- 15. Isbister GK, O'Regan L, Sibbritt D, Whyte IM. Alprazolam is relatively more toxic than other benzodiazepines in overdose. Br J Clin Pharmacol 2004; 58: 88-95.
- 16. Whyte IM, Dawson AH, Buckley NA, et al. A model for the management of self-poisoning. Med J Aust 1997; 167: 142-146.
- 17. Hardwicke C, Holt L, James R, Smith AJ. Trends in self-poisoning with drugs in Newcastle, New South Wales, 1980–1982. Med J Aust 1986; 144: 453-454.
- 18. Myers JB, Smith AJ, Elliott RL, MacAskill P. Self-poisoning with drugs: a 3 1/2-year study in Newcastle, NSW. Med J Aust 1981; 2: 402-405.
- 19. Buckley NA, Whyte IM, Dawson AH, Reith DA. Preformatted admission charts for poisoning admissions facilitate clinical assessment and research. Ann Emerg Med 1999; 34: 476-482.
- 20. Buckley NA, Whyte IM, Dawson AH, et al. Self-poisoning in Newcastle, 1987-1992. Med J Aust 1995; 162: 190-193.
- 21. Hawton K, Bergen H, Simkin S, et al. Toxicity of antidepressants: rates of suicide relative to prescribing and non-fatal overdose. Br J Psychiatry 2010; 196: 354-358.
- 22. Wolkin AF, Martin CA, Law RK, et al. Using poison center data for national public health surveillance for chemical and poison exposure and associated illness. Ann Emerg Med 2012; 59: 56-61.
- 23. van Gorp F, Whyte IM, Isbister GK. Clinical and ECG effects of escitalopram overdose. Ann Emerg Med 2009; 54: 404-408.
- 24. von Mach MA, Weber C, Meyer MR, et al. Comparison of urinary on-site immunoassay screening and gas chromatography-mass spectrometry results of 111 patients with suspected poisoning presenting at an emergency department. Ther Drug Monit 2007; 29: 27-39.
- 25. Rafnsson SB, Oliver JJ, Elton RA, Bateman DN. Poisons admissions in Edinburgh 1981–2001: agent trends and predictors of hospital readmissions. Hum Exp Toxicol 2007; 26: 49-57.
- 26. Lund C, Vallersnes OM, Jacobsen D, et al. Outpatient treatment of acute poisonings in Oslo: poisoning pattern, factors associated with hospitalization, and mortality. Scand J Trauma Resusc Emerg Med 2012; 20: 1.
- 27. Kapur N, Steeg S, Webb R, et al. Does clinical management improve outcomes following self-harm? Results from the multicentre study of self-harm in England. PLOS One 2013; 8: e70434.
- 28. Dawson AH, Eddleston M, Senarathna L, et al. Acute human lethal toxicity of agricultural pesticides: a prospective cohort study. PLOS Med 2010; 7: e1000357.
Publication of your online response is subject to the Medical Journal of Australia's editorial discretion. You will be notified by email within five working days should your response be accepted.