Comparison of zolpidem and zaleplon exposures in Texas, 1998-2004

Zolpidem and zaleplon are used for the treatment of insomnia. The objective of this study was to compare the patterns of zolpidem and zaleplon exposures reported to Texas poison control centers during 1998-2004. There were 5842 total reported zolpidem exposures, of which 2918 (50%) were isolated exposures, and 467 total reported zaleplon exposures, of which 201 (43%) were isolated exposures. Zolpidem patients were 62% male and 67% adult. Zaleplon patients were 67% male and 34% adult. The exposure was intentional in 62% of zolpidem and 58% of zaleplon exposures. The exposure occurred at the patient's own residence in 94% of zolpidem and 97% of zaleplon exposures. Management occurred outside of a health care facility for 29% of zolpidem and 32% of zaleplon exposures. The medical outcome involved no symptoms due to exposure for 29% of zolpidem and 44% of zaleplon exposures, a statistically significant difference. Although many of the most frequently reported adverse clinical effects for the two drugs were similar (drowsiness, slurred speech, hallucinations, ataxia, tachycardia, dizziness, confusion, vomiting), the proportion of exposures with a given adverse clinical effect was generally lower for zaleplon. Thus, although zolpidem and zaleplon exposures were generally similar with respect to patient gender and age, exposure reason and site, and management site, zaleplon exposures were less likely to result in minor medical outcomes or manifest as adverse clinical effects.