Reduced efficacy w/ CYP3A4 inducers. Increased bioavailability w/ macrolide antibiotics (eg, erythromycin), azole antifungal agents (eg, ketoconazole, itraconazole) or certain PIs (eg, ritonavir), grapefruit juice. Increased CNS depressant effects w/ other morphine derivatives (eg, analgesics & antitussives), general anaesth, skeletal muscle relaxants, sedative antidepressants, sedative H
1-antihistamines, barbiturates, anxiolytics (eg, benzodiazepines), hypnotics, antipsychotics, clonidine. Potentiated sedative effects w/ alcohol. Severe & unpredictable potentiation by MAOIs. Partially antagonised analgesic effect & induced w/drawal symptoms w/ partial opioid agonists/antagonists (eg, buprenorphine, nalbuphine, pentazocine). Increased risk of serotonin syndrome w/ serotonergic agent (eg, SSRI, SNRI or MAOI).