Evaluation of a specialty hepatitis C virus telephone pharmacy service

Purpose Direct-acting antivirals (DAAs) used to treat hepatitis C virus (HCV) infection are associated with significant drug-drug interactions (DDIs). Pharmacists are well positioned to identify and mitigate these DDIs. Data to guide assessment of the impact of HCV specialty pharmacy services on identifying and addressing DDIs with DAAs are lacking. The overall purpose of the study described here was to determine the incidence and severity of DDIs identified by specialty pharmacists among patients treated with DAAs prior to and 1 month into therapy. Methods An observational, retrospective study was conducted to evaluate the impact of specialty pharmacy services in mitigating DDIs associated with use of DAAs. Adult patients with HCV infection (n = 200) who received DAAs and were enrolled with a specialty pharmacy service over a 1-year period were included. Endpoints included number, severity, and type of DDIs and DDIs per patient at baseline and 1 month into therapy, pharmacists’ interventions, and safety and clinical outcomes. Results Fifty-nine percent of patients had at least 1 DDI. A total of 170 DDIs were identified (137 at baseline and 33 at 1-month follow-up), and the mean number of DDIs per patient significantly decreased from baseline to 1-month follow-up (from 1.38 to 0.16, P < 0.0001). The rate of “potentially clinically significant” or “critical” interactions was significantly lower at 1-month follow-up vs baseline assessment (69.6% vs 81.7%, P < 0.0001). The most commonly identified DDIs involved acid suppressive medications (49.6% and 66.6% of DDIs at baseline and follow-up assessment, respectively) and cardiovascular medications (26.2% and 21.2%, respectively). Total number of DDI interventions was 131, with an acceptance rate of 85%. Most common intervention was patient education and monitoring. Conclusion Approximately 60% of patients had DDIs with DAAs. Implementing HCV specialty pharmacy services significantly decreased DDIs while maintaining SVR12.