Coadministration has not been studied. Enzalutamide is primarily metabolized by CYP2C8 and can induce UGT1A1. Raltegravir is metabolized by UGT1A1 but has no inducing effects on CYPs. Coadministration may decrease raltegravir concentrations. Consider increasing raltegravir dose to 800 mg twice daily when coadministering with enzalutamide. Coadministration of once daily raltegravir is not recommended. Enzalutamide has a long half-life (5.8 days), therefore the raltegravir dose should be kept at 800 mg twice daily for a minimum of 2 weeks (but preferably 4 weeks) following cessation of enzalutamide due to the persisting inducing effect upon discontinuation of a strong inducer.