Comparative Pharmacology
Head-to-head clinical analysis: DARVON COMPOUND 65 versus DARVON N W ASA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON COMPOUND 65 versus DARVON N W ASA.
DARVON COMPOUND-65 vs DARVON-N W/ ASA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Propoxyphene is a weak opioid agonist that binds to mu-opioid receptors in the CNS, altering pain perception. Aspirin inhibits cyclooxygenase (COX-1 and COX-2), reducing prostaglandin synthesis, which mediates pain, fever, and inflammation.
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.
1-2 capsules (propoxyphene napsylate 100 mg / aspirin 325 mg per capsule) orally every 4 hours as needed for pain; maximum 6 capsules per day.
None Documented
None Documented
Propoxyphene: 6-12 hours (mean 8 h); nordextropropoxyphene: 22-30 hours (accumulates with repeated dosing; risk of toxicity)
Propoxyphene: terminal elimination half-life is 6-12 hours in adults with normal renal function; norpropoxyphene has a longer half-life (30-36 hours). Aspirin (as salicylate): half-life is dose-dependent, ranging from 2-3 hours at low doses to 15-30 hours at anti-inflammatory doses (300-600 mg in Darvon-N W/ASA).
Renal: ~90% as propoxyphene and metabolites (nordextropropoxyphene); biliary/fecal: ~10%
Renal: propoxyphene and its metabolites (norpropoxyphene) are primarily eliminated via kidneys, with ~20-25% excreted unchanged; fecal: minor; biliary: some enterohepatic recirculation occurs, but exact % are not well quantified for the combination product. Aspirin is hydrolyzed to salicylate, which is excreted renally (75% as salicyluric acid, 10% as salicylic acid, 10% as glucuronide conjugates, and minor amounts as gentisic acid).
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination