Coadministration has not been studied but based on metabolism and clearance a pharmacokinetic interaction is unlikely. Terfenadine undergoes extensive metabolism by CYP3A4. Cabotegravir and rilpivirine have no effect on midazolam (a sensitive CYP3A4 substrate) in healthy subjects. Rilpivirine has been associated with prolongation of the QTc interval at supra-therapeutic doses but these are unlikely to occur when coadministered with terfenadine. However, given the known QT prolongation risk associated with terfenadine, caution is recommended.