Biperiden/fentanyl: Psychomotor agitation and delirium: case report

A 63-year-old woman with cancer started receiving fentanyl patches ('normal dosage') for chest and back pain. On day 3 she developed restlessness, anxiety and became talkative. Haloperidol was initiated without improvement. She also reported thirst and was agitated. She was diagnosed with psychomotor agitation [akathisia] and haloperidol was switched to cloxazolam. The next day she was still restless and IM biperiden 5mg was administered. She became increasingly disorientated and confused, indicating delirium [time to reaction onset not stated]. The delirium improved the next day.Author Comment"This case suggests that in cancer patients, administration of biperiden intensifies the cholinergic activity of sedatives such as fentanyl, and may lead to delirium."