Transdermal fentanyl: pharmacology and toxicology.
OBJECTIVE
To evaluate the underlying pharmacology, safety, and misuse/abuse of transdermal fentanyl, one of the cornerstone pharmacotherapies for patients with chronic pain.


METHODS
Literature was identified through searches of Medline (PubMed) and several textbooks in the areas of pharmacology, toxicology, and pain management. A bibliographical review of articles identified by these searches was also performed. Search terms included combinations of the following: fentanyl, transdermal, patch, pharmacology, kinetics, toxicity, and poisoning. All pertinent clinical trials, retrospective studies, and case reports relevant to fentanyl pharmacology and transdermal fentanyl administered by any route and published in English were identified. Each was reviewed for data regarding the clinical pharmacology, abuse, misuse, and safety of transdermal fentanyl. Data from these studies and information from review articles and pharmaceutical prescribing information were included in this review.


RESULTS
Fentanyl is a high-potency opioid that has many uses in the treatment of both acute and chronic pain. Intentional or unintentional misuse, as well as abuse, may lead to significant clinical consequences, including death. Both the US Food and Drug Administration (FDA) and Health Canada have warned of potential pitfalls associated with transdermal fentanyl, although these have not been completely effective in preventing life-threatening adverse events and fatalities related to its inappropriate use.


CONCLUSIONS
Clinically consequential adverse effects may occur unexpectedly with normal use of transdermal fentanyl, or if misused or abused. Misuse and therapeutic error may be largely preventable through better education at all levels for both the prescriber and patient. The prevention of intentional misuse or abuse may require regulatory intervention.
Nelson
Lewis
L
Department of Emergency Medicine, New York University School of Medicine, New York City Poison Control Center, New York, New York 10016, USA. lewis.nelson@nyumc.org
Schwaner
Robert
R
D000279:Administration, Cutaneous; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000266:history / Q000493:pharmacokinetics / Q000506:poisoning*; D002908:Chronic Disease; D004337:Drug Carriers; D062787:Drug Overdose; D005283:Fentanyl / Q000008:administration & dosage* / Q000266:history / Q000493:pharmacokinetics / Q000506:poisoning*; D049673:History, 20th Century; D006801:Humans; D009293:Opioid-Related Disorders / Q000209:etiology* / Q000401:mortality / Q000517:prevention & control; D010146:Pain / Q000188:drug therapy*; D018570:Risk Assessment
D000701:Analgesics, Opioid; D004337:Drug Carriers; D005283:Fentanyl