BACKGROUND: Direct-acting antiviral (DAA) regimens for hepatitis C virus (HCV) have varying potentials for drug-drug interactions (DDIs). OBJECTIVES: To (1) identify prevalence of potential DDI with glecaprevir-pibrentasvir (GLE-PIB) and sofosbuvir-velpatasvir (SOF-VEL) and (2) describe health care provider actions in response to pharmacist recommendations based on potential interactions with GLE-PIB or SOF-VEL, using 2 complementary data sources. METHODS: Possible interacting drugs were identified among adult patients in a United States electronic medical record database covering 21 health care organizations and 26 million patients in 2018. DDIs were categorized as potential weak interaction (Level 1), potential interaction (Level 2), or contraindicated (Level 3). Real-world recommendations and resultant actions regarding DDIs with GLE-PIB and SOF-VEL were obtained from a specialty pharmacy database. Categorical variable comparisons were done via chi-square analysis with subsequent z-tests of column proportions. RESULTS: DDI prevalence was higher for patients prescribed GLE-PIB (317/769 [41%]) compared with those prescribed SOF-VEL (170/633 [27%]), and the prevalence of a Level 3 (contraindicated) interaction was higher with GLE-PIB than SOF-VEL (61/769 [8%] vs 2/633 [< 1%]). Across all DDI levels, analgesics (139/317 [44%]), proton-pump inhibitors (129/317 [41%]), and lipid-lowering agents (59/317 [19%]) were the top drug classes for the GLE-PIB group with potential for DDI. For SOF-VEL prescribed patients, the top drug classes were proton-pump inhibitors (83/170 [49%]), histamine-2 blockers (42/170[25%]), and lipid-lowering agents (42/170 [25%]). In real-world care management, the overall prevalence of pharmacist recommendations regarding DDIs was significantly lower for SOF-VEL (28/419 [7%]) relative to GLE-PIB (151/1,216 [12%]). Recommended guidance from pharmacists was not followed for 39% (69/179) of patients, 36% (54/151) for GLE-PIB, and 54% (15/28) for SOF-VEL. CONCLUSIONS: The potential for DDIs with pangenotypic HCV DAAs is frequent and may be more frequent with GLE-PIB than SOF-VEL. Physician responses to pharmacist alerts regarding potential interaction can be highly variable, even in cases of contraindication. DISCLOSURES: Funding for this study was provided by Gilead Sciences, Inc. Trio Health Analytics received funding from Gilead Sciences, Inc., to conduct research for this study. Tsai consults for and has received grants and honoraria from Gilead, AbbVie, Merck, and Bristol Myers Squibb; he has also received lecture fees from Gilead and AbbVie. Curry consults for Trio Health Analytics and Gilead and has also consulted for and received grants from Mallinckrodt. Flamm consults for and has received lecture fees from Gilead and AbbVie; he has also received grants from Gilead and AbbVie. Milligan and Wick are employed by Trio Health Analytics and have received research support from Gilead, Merck, and AbbVie. Younossi has received grants from Gilead, Intercept, Bristol Myers Squibb, GlaxoSmithKline, and Novo Nordisk. Afdhal is a paid consultant/advisory board member for Gilead, Echosens, Ligand, Shionogi, and Trio Health; owns stock in Spring-Bank and Allurion and has stock options in SpringBank; receives royalty income from UpToDate; and is on the board of directors for the nonprofit Liver Institute for Education and Research. Data from this study were presented at the American Association for the Study of Liver Disease (AASLD) Liver Meeting 2019; November 8-12, 2019; Boston, MA, and the European Association for Study of the Liver (EASL) International Liver Congress 2020; August 27-29, 2020; virtual.