Concomitant Use of Cotrimoxazole and Atazanavir in HIV-infected Patients: A Therapeutic Drug Monitoring and Pharmacovigilance Based Dual Approach.

Background: Cotrimoxazole is the main antibiotic used in primary prophylaxis for opportunistic infections in advanced HIV infection. This drug can inhibit one of the metabolic pathways of atazanavir (ATV), such as the cytochromes P450 (CYP) 2C8/2C9 and could interfere with its safety and efficacy.

Objective: We studied the drug-drug interaction (DDI) between cotrimoxazole and ATV by using therapeutic drug monitoring (TDM) and pharmacovigilance (PV) approaches.