Prospective multicenter study of the epidemiological features of emergency patients with overdose of over-the-counter drugs in Japan.

Aim: To investigate the epidemiological characteristics of patients presenting to the emergency department with an overdose of over-the-counter (OTC) drugs. Methods: A questionnaire survey was conducted to examine the sociodemographic characteristics of patients with OTC drugs overdoses visiting emergency departments at eight sites across the country. The patients were divided into "habitual" and "nonhabitual" groups according to their history of OTC drugs overdose. Student's Results: Of the 124 patients included in this study, 79% were women. The habitual (26.6%) and the nonhabitual (73.4%) groups showed no differences in sex, occupation, cohabitants, history of mental illness, or history of alcohol consumption or smoking; however, those in the habitual group were significantly younger. The proportion of OTC drugs obtained from physical stores was higher in the habitual group, whereas the nonhabitual group used more household medicines. Suicide and self-harm were more common reasons for overdose in the nonhabitual group. Antipyretic analgesics were significantly more common in the nonhabitual group, whereas antitussive expectorants and antihistamines were significantly more common in the habitual group. Conclusion: This is the first multicenter study to determine the status of OTC drugs overdose patients treated at emergency departments of medical facilities in Japan. To prevent new overdoses of OTC drugs, continued detailed epidemiologic studies of patient backgrounds and drug acquisition routes, and investigation of the components of OTC drugs that cause dependency are necessary.