South African healthcare workers' knowledge of dolutegravir's drug-drug interactions in the first year of its rollout: a cross-sectional online survey

Introduction In December 2019, dolutegravir-based treatment was recommended as first-line antiretroviral therapy (ART) in South Africa. Dolutegravir has clinically significant interactions with several commonly used drugs, such as rifampicin, metformin and cation-containing medicines. National guidelines detail these interactions and how to manage them. While previous international studies have shown low healthcare worker knowledge of drug-drug interactions, there is a paucity of information on antiretroviral interaction knowledge in the South African setting, where much ART is nurse-led. The study aimed to determine this knowledge and to describe which variables were associated with gaps in knowledge. Methods An anonymous online survey of healthcare workers in the field of HIV was conducted in August/September 2020. The survey was designed, tested and piloted, and included sections on demographics, guideline access and training, interaction knowledge, counselling and the effect of COVID-19. Dissemination was via e-mail and social media (convenience sampling). Descriptive and inferential analysis was done using proportions and the 95% confidence interval to determine relationships between independent and dependent variables. Research ethics approval was obtained from the University of Cape Town's Human Research Ethics Committee (HREC Ref: 357/2020). Results and discussion In total, 1950 survey responses were included in the analysis - 47.1% nurses, 35.8% doctors and 8.9% pharmacists. When asked whether they were aware that dolutegravir has interactions, 70% said yes, 13.9% said no and 16.1% did not answer. Knowledge of specific interactions and the dosing changes needed was low with a wide range between different drugs: 79.7% knew to double the dolutegravir dose with rifampicin, but with calcium, 5.1% picked both correct dosing options and 33.7% picked one of the two correct options. Access to guidelines and training were positively associated with drug interaction knowledge. Conclusions There are gaps in the awareness and knowledge of dolutegravir interactions and how to adjust dosing among South African healthcare workers.