Ritonavir (Norvir) and methadone.
D001682:Biological Availability; D015658:HIV Infections / Q000188:drug therapy*; D017320:HIV Protease Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D008691:Methadone / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019438:Ritonavir / Q000009:adverse effects / Q000627:therapeutic use*
D017320:HIV Protease Inhibitors; D019438:Ritonavir; D008691:Methadone