The safety of oseltamivir in patients with influenza: analysis of healthcare claims data from six influenza seasons.

Context: Recently, neuropsychiatric events associated with oseltamivir treatment have been reported, mainly in pediatric patients in Japan.

Objective: To explore the influence of oseltamivir treatment on central nervous system (CNS)-related and neuropsychiatric events in adults, children, and adolescents with influenza.

Design: A retrospective cohort study using propensity-matched data for 6 influenza seasons (2000-2006).

Setting: Claims data were obtained from the Thomson Healthcare MarketScan Research Database.

Patients: Patients of all ages and in subgroups aged 12 years or younger, 13-17 years, and 18-49 years diagnosed with influenza.

Main outcome measures: Claims for CNS and neuropsychiatric events within 14 and 30 days following influenza diagnosis were compared between patients prescribed oseltamivir and those not prescribed antiviral treatment.

Results: Data for 40,704 patients prescribed oseltamivir (9599 aged 12 years or younger; 4615, 13-17 years; and 16,910, 18-49 years) and 40,704 matched controls (9599 aged 12 years or younger; 4621, 13-17 years; and 16,898, 18-49 years) were analyzed. None of the CNS-related and neuropsychiatric events was more likely to occur in patients prescribed oseltamivir. Overall, CNS-related or neuropsychiatric events (odds ratio [OR] 0.76; 95% confidence intervals [CI]: 0.68, 0.84), psychiatric events (OR 0.82; 95% CI: 0.70, 0.96), and disturbances of consciousness (OR 0.61; 95% CI: 0.48, 0.76) within 14 days after influenza diagnosis were all less likely in patients given oseltamivir. Findings were similar within the 30-day post-index time window and across all age groups.

Conclusions: No increase in CNS-related and neuropsychiatric events was observed in adults, children, or adolescents with influenza who were prescribed oseltamivir in this study.