Drugs suspected to be involved in the DDI-summary
Complete list of drugs taken by the patient
Clinical case description
An overall healthy man living with was on ART for more 5 years, including two InSTI-based ARV regimens (FTC/TAF/EVGc and FTC/TAF/BIC). He always presented undetectable viral load since the first control on ART, more than 4 years ago, and always reported good adherence to ART. He had no other relevant medical history and he was not taking any other regular medication apart from ART.
In September 2021, he presented with detectable VL at 70 copies/mL for the first time since ART initiation (5 years before). He denied any adherence problems or any new medication but he referred had started two months before a vitamin supplement which included Mg2+. It was indicated to stop this supplement and VL was repeated 2 months later, becoming undetectable again.
Drug Interaction Probability Scale (DIPS)
Bictegravir binds to divalent cations, such as magnesium, and forms a complex at the level of the gastro-intestinal tract which results in less bictegravir being absorbed. Biktarvy should not be co-administered simultaneously with divalent cations under fasted conditions. Biktarvy should be administered at least 2 hours before mineral supplements containing calcium, iron, aluminium or magnesium, or taken simultaneously with food. Biktarvy should be administered at least 2 hours before, or 6 hours after antacids containing magnesium and/or aluminium.