Comparative Pharmacology
Head-to-head clinical analysis: DARVON N versus OPANA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N versus OPANA.
DARVON-N vs OPANA
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.
Mu-opioid receptor agonist; produces analgesia by binding to opioid receptors in the CNS, inhibiting ascending pain pathways and altering pain perception.
100 mg orally every 4 hours as needed for pain; maximum 600 mg per day.
5-20 mg orally every 4-6 hours as needed for pain; extended-release tablets: 5 mg orally every 12 hours, titrated up to 20 mg every 12 hours.
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 is 11-16 hours (mean 14 hours) in adults; prolonged in hepatic impairment (up to 30 hours) and elderly.
Primarily renal (approximately 70% as unchanged drug and glucuronide conjugates); minor biliary/fecal elimination (25-30%).
Primarily renal (approximately 90% as conjugated metabolites, 10% unchanged); biliary/fecal elimination accounts for <10%.
Category C
Category C
Opioid Analgesic
Opioid Analgesic