Comparative Pharmacology
Head-to-head clinical analysis: DARVON N W ASA versus PERCODAN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N W ASA versus PERCODAN.
DARVON-N W/ ASA vs PERCODAN
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 opioid agonist with relative selectivity for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of oxycodone is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia. Oxycodone acts on the central nervous system (CNS) to produce analgesia. Aspirin inhibits cyclooxygenase, leading to decreased prostaglandin synthesis, which reduces pain and inflammation.
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.
1-2 tablets orally every 4-6 hours as needed for pain. Each tablet contains oxycodone 4.5 mg and aspirin 325 mg.
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: 3-5 hours, prolonged in elderly, hepatic/renal impairment. Aspirin: 2-3 hours at low doses; 15-30 hours at anti-inflammatory doses due to saturable metabolism.
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).
Oxycodone: primarily renal (65-87% as parent and metabolites, mostly noroxycodone and oxymorphone conjugates); ~10% fecal. Aspirin: renal (75-90% as salicylates and metabolites, dose-dependent).
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination