Coadministration is contraindicated as it may significantly decrease concentrations of elvitegravir and cobicistat, which may result in loss of therapeutic effect and development of resistance.

Coadministration with intramuscular cabotegravir and rilpivirine has not been studied and is contraindicated due to the risk of sub-therapeutic concentrations and the related risk of the development of resistance. Coadministration of rifampicin (600 mg once daily) and oral cabotegravir (30 mg once daily) decreased cabotegravir Cmax, AUC and C24 by 6%, 59% and 50%, respectively. Similarly to oral cabotegravir, concomitant administration with rifampicin is not recommended with intramuscular cabotegravir. Furthermore, significant decreases in rilpivirine plasma concentrations are expected. Coadministration of rilpivirine (150 mg once daily) and rifampicin (600 mg once daily) decreased rilpivirine Cmax, AUC and Cmin by 69%, 80% and 89%, respectively. There was no significant effect on rifampicin. Coadministration is contraindicated due to the potential for loss of therapeutic effect and development of resistance. Using PBPK modelling, rifampicin was predicted to reduce the exposure of long-acting intramuscular cabotegravir by 61% and rilpivirine by 38%. The interaction with rifampicin was not overcome by shortening the dosing interval of intramuscular cabotegravir and rilpivirine.

Coadministration has not been studied but based on metabolism and clearance, a clinically significant interaction is unlikely. Ashwagandha extracts had no effect on CYP enzymes in vitro.

Coadministration has not been studied but based on metabolism and clearance, a clinically significant interaction is unlikely. No effect is expected on rilpivirine as ashwagandha extracts had no effect on CYP enzymes in vitro. No effect is expected on cabotegravir as it is mainly metabolized by UGT1A1 and to a lesser extent by UGT1A9.