Dolutegravir and rifampicin interaction – real-life virologic outcomes of Namibians with HIV and tuberculosis

Dolutegravir and rifampicin are often used together when treating patients coinfected with HIV and tuberculosis. Guidelines recommend increasing the dose of dolutegravir to 50 mg twice daily when administered with rifampicin due to strong CYP450 enzyme induction. A retrospective cohort study was conducted to determine the percentage of patients with appropriate dolutegravir dose adjustments and the rates of viral suppression after tuberculosis treatment. Forty-nine persons with HIV and tuberculosis receiving dolutegravir and rifampicin in Namibia were identified; 65.3% were male, and the median baseline CD4 cell count was 126 cells/mm3 (IQR 52.5-258). Dolutegravir dose was appropriately increased to 50 mg twice daily in 65.3% of patients, and those patients were more likely to achieve a viral suppression of less than 1,000 copies/ml (p < 0.05), but not less than 200 copies/ml (p = 0.2). Also, patients who were virologically suppressed before starting tuberculosis treatment were more likely to be suppressed at the end of tuberculosis therapy regardless of dolutegravir dose (p < 0.05).