Comparative Pharmacology
Head-to-head clinical analysis: DARVON N versus DURAGESIC 25.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N versus DURAGESIC 25.
DARVON-N vs DURAGESIC-25
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Propoxyphene is a weak mu-opioid receptor agonist that produces analgesia by binding to opioid receptors in the central nervous system, altering the perception of and response to pain. Its metabolite norpropoxyphene has local anesthetic and sodium channel blocking effects, which may contribute to cardiac toxicity.
Fentanyl is a mu-opioid receptor agonist that produces analgesia and sedation by mimicking endogenous opioids in the central nervous system.
100 mg orally every 4 hours as needed for pain; maximum 600 mg per day.
Apply 25 mcg/hour transdermally every 72 hours; initial dose in opioid-naive patients: 25 mcg/hour is not recommended; use lower strength or immediate-release opioid first.
None Documented
None Documented
Propoxyphene: 6-12 hours; norpropoxyphene: 30-36 hours. Accumulation of norpropoxyphene on repeated dosing increases risk of toxicity.
Terminal elimination half-life 22-25 hours (range 13-31 h) after 72-h transdermal application; prolonged in elderly, hepatic or renal impairment
Primarily renal (approximately 70% as unchanged drug and glucuronide conjugates); minor biliary/fecal elimination (25-30%).
Renal (75% as metabolites, <10% unchanged); fecal (9%)
Category C
Category C
Opioid Analgesic
Opioid Analgesic