Ældre personer, kakektiske eller svækkede patienter kan have en reduceret fentanyl- clearance, og det aktive stof kan derfor have en forlænget, terminal halveringstid hos disse patienter.
Elderly, cachectic, or debilitated patients may have a reduced clearance of fentanyl and, therefore, the active substance may have a prolonged terminal half-life in these patients.