Comparative drug dose and drug combinations in patients that present to hospital due to self-poisoning.

Self-poisoning is a common reason for acute presentation to hospital. Commonly involved drugs have been reported, but few data exist concerning the different combinations of agents or comparative doses ingested. The present study sought to better characterise the typical patterns of drug overdose that may present via the emergency department. Consecutive adults ≥16 years of age that presented to York Hospital owing to self-poisoning were studied for 2010-2011 inclusive. The primary outcome measure was reported dose, expressed as a multiple of the defined daily dose (DDD) to allow comparison between different agents. There were 1024 patients, including 622 women (60.7%), and median age was 32 years (range, 16 to 92 years). Overdose in men was associated with a higher overall quantity of drugs: arithmetic mean of 20 DDD multiples (95% CI, 15-26) versus 13 (11-15), p = 0.001. Overdose involved a single agent only in 538 patients (52.5%). The mean paracetamol dose was 4.0 (95% CI, 3.7-4.3) DDD multiples; the doses of antidepressants (19.4, 17.0-21.7, p < 0.0001) and benzodiazepines (18.0, 12.8-23.2, p < 0.0001) were comparatively higher. The types of agents involved in self-poisoning and common combinations of agents are characterised. Psychotropic medications were ingested in comparatively larger quantities than analgesic agents and had worse clinical outcome. Further work is required to understand the factors that determine the quantity of drug ingested in patients at risk of drug overdose so as to minimise the risk of significant toxicity.