Patient characteristics associated with nonprescription drug use in intentional overdose

Over-the-counter (OTC) medications remain freely available to suicidal patients, despite their potential lethality and common use in suicide. The study's main objective was to identify patient characteristics, particularly psychiatric diagnosis associated with the use of OTC medications in intentional overdose.

We retrospectively reviewed 95 charts from patients who presented to St Paul's Hospital from August 1, 1997, to July 31, 1998, with a discharge diagnosis of intentional drug overdose. Univariate analysis was carried out to identify potential risk markers for OTC medication use, and logistic regression was performed using these variables.

When the variables age, sex, and concurrent psychiatric diagnoses were controlled, use of OTC medications in overdose was significantly lower in patients with a DSM-IV diagnosis of substance abuse (OR 0.11, P = 0.005) and in those who possessed prescription medications at the time of overdose (OR 0.18, P = 0.007). Most patients in this cohort (82%) had at least 1 of these 2 traits. Although not statistically significant, younger patients appeared more likely to choose OTC medications for overdose.

Suicide-prone patients with a diagnosis of substance abuse and who possess prescription medications are unlikely to use OTC medications in overdose. For this cohort, this represents a relatively small proportion of patients whom clinicians should consider to be at greater risk for attempting suicide when using OTC medication, especially acetaminophen.