Comparative Pharmacology
Head-to-head clinical analysis: DARVOCET N 50 versus OPANA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVOCET N 50 versus OPANA.
DARVOCET-N 50 vs OPANA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Propoxyphene is a weak mu-opioid receptor agonist; it also binds to sigma receptors. Acetaminophen inhibits prostaglandin synthesis via COX-1 and COX-2, thereby reducing pain and fever.
Mu-opioid receptor agonist; produces analgesia by binding to opioid receptors in the CNS, inhibiting ascending pain pathways and altering pain perception.
1 tablet (propoxyphene 50 mg, acetaminophen 300 mg) orally every 4 hours as needed for pain, not to exceed 6 tablets 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
Acetaminophen: 1.5-3 hours (therapeutic); 4-6 hours in overdose due to saturation of metabolism. Propoxyphene: 6-12 hours (parent); norpropoxyphene: 30-36 hours (active metabolite, accumulates with repeated dosing).
Terminal elimination half-life is 11-16 hours (mean 14 hours) in adults; prolonged in hepatic impairment (up to 30 hours) and elderly.
Acetaminophen: renal (90-100% as metabolites within 24h; 2-4% unchanged). Propoxyphene: renal (25-30% unchanged; metabolites) and biliary/fecal (significant enterohepatic circulation).
Primarily renal (approximately 90% as conjugated metabolites, 10% unchanged); biliary/fecal elimination accounts for <10%.
Category C
Category C
Opioid Analgesic
Opioid Analgesic