Coadministration has not been studied with intramuscular cabotegravir and rilpivirine. Coadministration of rifampicin (600 mg once daily) and oral cabotegravir (30 mg once daily) decreased cabotegravir Cmax by 6%, AUC by 59% whereas oral clearance was increased by 2.4 fold. A similar effect is expected with carbamazepine, therefore coadministration is not recommended with intramuscular cabotegravir. In addition, carbamazepine is expected to substantially decrease rilpivirine exposure. Thus coadministration is contraindicated due to the potential for loss of therapeutic effect and development of resistance.