In brief: heat and transdermal fentanyl.
Transdermal fentanyl (Duragesic, and others) offers a convenient delivery system for patients with chronic pain but it has some drawbacks. One is that exposing the patch to heat, either from an external source, increased exertion or possibly high fever, could increase release of the drug, which might lead to an overdose and fatal respiratory depression. A recent article in the NY Times about this problem may have aroused the concerns of some patients using the patches.
D000279:Administration, Cutaneous; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D003692:Delayed-Action Preparations; D062787:Drug Overdose; D005283:Fentanyl / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D006358:Hot Temperature; D006801:Humans; D009292:Narcotic Antagonists / Q000627:therapeutic use; D010146:Pain / Q000188:drug therapy; D012131:Respiratory Insufficiency / Q000139:chemically induced
D000701:Analgesics, Opioid; D003692:Delayed-Action Preparations; D009292:Narcotic Antagonists; D005283:Fentanyl