Comparative Pharmacology
Head-to-head clinical analysis: DARVOCET A500 versus DARVON COMPOUND 65.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVOCET A500 versus DARVON COMPOUND 65.
DARVOCET A500 vs DARVON COMPOUND-65
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination analgesic: acetaminophen inhibits cyclooxygenase (COX) and modulates endocannabinoid system; propoxyphene is a mu-opioid receptor agonist.
DARVON COMPOUND-65 contains propoxyphene, a centrally acting opioid agonist with analgesic effects primarily mediated through mu-opioid receptors. Aspirin inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis. Caffeine is a CNS stimulant with additive analgesic effects.
One tablet (500 mg acetaminophen, 100 mg propoxyphene napsylate) orally every 4 hours as needed for pain; maximum 6 tablets per day.
1 capsule (propoxyphene HCl 65 mg, aspirin 389 mg, caffeine 32.4 mg) orally every 4 hours as needed for pain; maximum 6 capsules per day.
None Documented
None Documented
Propoxyphene: 6-12 hours (terminal, prolonged in elderly, hepatic impairment, or overdose). Acetaminophen: 2-3 hours (terminal, prolonged in hepatic impairment or overdose).
Propoxyphene: 6-12 hours (mean 8 h); nordextropropoxyphene: 22-30 hours (accumulates with repeated dosing; risk of toxicity)
Propoxyphene: ~20-25% renal as unchanged drug, ~35% as norpropoxyphene, ~20% biliary/fecal. Acetaminophen: ~2-4% renal unchanged, ~85% as glucuronide and sulfate conjugates, ~5% as cysteine and mercapturate conjugates.
Renal: ~90% as propoxyphene and metabolites (nordextropropoxyphene); biliary/fecal: ~10%
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination