Abuse, dependence and withdrawal associated with fentanyl and the role of its (designated) route of administration: an analysis of spontaneous reports from Europe.

In suspected cases of abuse, dependence or withdrawal, fentanyl was mainly used for non-cancer pain indications and most often as transdermal formulations. Depression and prolonged hospitalisations were common, especially in patients with musculoskeletal disorders, indicating a vulnerable patient group and complex treatment situations.