Potential Drug-Drug Interactions Between Oral Antiviral Agents Used for Hepatitis B Treatment and Concomitant Systemic Medications

Objectives: Antiviral therapy planning for hepatitis B (HB) requires consideration of drug interactions. The aim of this study was to evaluate the potential drug-drug interactions (pDDIs) between oral antiviral drugs and concomitant medications for hepatitis. Materials and Methods: HB patients who received oral antiviral therapy in our clinic were included. Identified pDDIs were categorized as level 1 (weak potential interaction), level 2 (potential interaction), or level 3 (contraindicated) according to the University of Liverpool Hepatitis Drug Interaction Database. Results: Of the 205 patients included in the study, 112 (54.6%) received tenofovir disoproxil fumarate (TDF), 65 (31.7%) received entecavir (ETV), and 28 (13.7%) received tenofovir alafenamide fumarate (TAF). Patients receiving TDF, ETV, and TAF received 135, 119, and 52 concomitant systemic medications, respectively. Twenty-level 2 and two level 1 interactions were observed, but no level 3 interactions. Potential DDIs were observed in 12.6% of patients receiving TDF, 3.4% receiving ETV, and 1.9% receiving TAF. The most common pDDIs were observed with non-steroidal anti-inflammatory drugs (noted in 12 occurrens and all with TDF). Conclusion: The combination of antivirals used for chronic HB treatment with systemic drugs can lead to pDDIs, especially with TDF. All patients with HB should be screened for pDDI.