DDI risk during oral lead in phase
Intramuscular administration of cabotegravir and rilpivirine has the advantage of eliminating first pass metabolism and DDIs occurring at the gastrointestinal level. However, there are a number of drug interactions for cabotegravir and rilpivirine that are clinically relevant during the oral lead-in phase. Divalent metal cations (e.g. Ca2+, Al2+, Mg2+, Fe2+, Zn2+) for example calcium containing antacids and some multivitamins chelate with cabotegravir in the gut and can decrease absorption and therefore dosing with oral cabotegravir must be separated by at least 2 hours before or 4 hours after such medications . Rilpivirine requires an acidic gastric environment to facilitate absorption and therefore proton-pump inhibitors decrease rilpivirine exposure when taken orally .