Comparative Pharmacology
Head-to-head clinical analysis: DARVOCET N 50 versus DEMEROL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVOCET N 50 versus DEMEROL.
DARVOCET-N 50 vs DEMEROL
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.
Meperidine is an opioid agonist that binds to mu-opioid receptors in the central nervous system, mimicking endogenous endorphins to produce analgesia, sedation, and euphoria. It also has additional weak actions at kappa and delta receptors.
1 tablet (propoxyphene 50 mg, acetaminophen 300 mg) orally every 4 hours as needed for pain, not to exceed 6 tablets per day.
50-150 mg IM, IV, or SC every 3-4 hours as needed for pain; oral 50-150 mg every 3-4 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).
2.5-4 hours; prolonged in hepatic impairment (7-11 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).
Renal (90% as metabolites and unchanged drug; ~5% unchanged) and biliary/fecal (minor).
Category C
Category C
Opioid Analgesic
Opioid Analgesic