BackgroundLimited studies have evaluated the effectiveness of pharmacist interventions on outpatient prescription. The goal of this study was to evaluate the clinical and economic impacts of pharmacist interventions on randomly sampled outpatient prescriptions.MethodOutpatient prescriptions of our hospital were sampled automatically and reviewed by pharmacists since 2011. Pharmacists intervened in inappropriate prescriptions (IPs) real-timely, and summarized and analyzed the information monthly. Cost-benefit analysis was performed to estimate the economic benefit of the pharmacist intervention.ResultsFrom 2011 to 2016, pharmacists reviewed 101,271 prescriptions and intervened in 5155 prescriptions. With the interventions of pharmacists, the number of IPs decreased from 1845 to 238, while the inappropriate percentage decreased from 12.60 to 1.22%. The inappropriate rates of different departments and the types decreased annually. IPs were mainly from the Department of Medicine and Department of Surgery and category 1 (Non-indicated medications) in all years. The benefit-to-cost ratios of pharmacist interventions were always more than 1. In the same years, the benefit-to-cost ratios in public payments were higher than those with insurance and self-payment.ConclusionThis form of pharmacist intervention constitutes a method that showed positive clinical and economic benefits and is worth expanding in large hospitals. Pharmacists should pay more attention on prescriptions in department of surgery or prescriptions with public payments.