Fentanyl Increased AST and ALT: case reportIn a study, a patient [age and sex not stated] was identified who developed an increased AST and ALT while receiving fentanyl. The patient, who had a history of lung cancer, was started on transdermal fentanyl once daily patch [dose not stated] for cancer-associated pain. Nine days after starting the transdermal patch, the patient developed a grade 2 increase in AST and ALT. Fentanyl was switched to oxycodone. Subsequently, the AST and ALT had normalised.Author comment: "[A]n adverse hepatic effect was observed in one patient, in which a grade II increase in aspartate transaminase (AST) and alanine transaminase (ALT) levels occurred nine days after commencing treatment with the [fentanyl] patch."Takakuwa O, et al. Long-Term use of a once-a-day fentanyl citrate transdermal patch in lung cancer patients.