Coadministration has not been studied but based on metabolism and clearance a clinically significant interaction is unlikely. Psilocybin is rapidly dephosphorylated to psilocin which is responsible for the hallucinogenic effects. Psilocin is deactivated to multiple metabolites by alcohol dehydrogenase and monoamine oxidase or glucuronidated to psilocin-O-glucuronide by UGT1A9 in the liver or UGT1A10 in the small intestine before excretion in the urine. Cabotegravir is mainly metabolized by UGT1A1 and to a lesser extent by UGT1A9. Rilpivirine is metabolized by CYP3A4. Cabotegravir/rilpivirine is unlikely to affect psilocybin or psilocin metabolism. Psilocybin and psilocin are unlikely to affect UGT1A1, UGT1A9 or CYP3A4.