Comparative Pharmacology
Head-to-head clinical analysis: DARVON N W ASA versus PERCODAN DEMI.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N W ASA versus PERCODAN DEMI.
DARVON-N W/ ASA vs PERCODAN-DEMI
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Oxycodone is a full mu-opioid receptor agonist; aspirin inhibits cyclooxygenase (COX-1 and COX-2), reducing prostaglandin synthesis.
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.
1 tablet (oxycodone 2.25 mg/aspirin 325 mg) orally every 6 hours as needed for pain; maximum 4 tablets in 24 hours.
None Documented
None Documented
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).
Oxycodone: 3-4 hours; salicylate (aspirin): 2-3 hours at low doses, 15-30 hours at high doses; terminal half-life clinically relevant for dosing interval (q4-6h).
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).
Renal: ~90% (oxycodone: ~60% as metabolites, ~10% unchanged; aspirin: ~80% as salicylates, ~10% unchanged). Biliary/fecal: minor.
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination