Comparative Pharmacology
Head-to-head clinical analysis: DARVON N W ASA versus PERCOCET.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N W ASA versus PERCOCET.
DARVON-N W/ ASA vs PERCOCET
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 mu-opioid receptor agonist, inhibiting ascending pain pathways and altering pain perception and emotional response. Acetaminophen inhibits cyclooxygenase (COX) in the CNS, reducing prostaglandin synthesis and exerting analgesic and antipyretic effects.
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.
One tablet (5 mg oxycodone/325 mg acetaminophen) every 6 hours as needed for pain; maximum 12 tablets per day.
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: 3.5–4.5 hours (terminal) in normal renal function; prolonged in hepatic/renal impairment (up to 6–12 hours). Acetaminophen: 2–3 hours (terminal) in overdose, extended with hepatic injury.
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 (up to 19% as unchanged drug, 50% as noroxycodone and oxymorphone metabolites); about 10% biliary/fecal. Acetaminophen: renal (majority as glucuronide and sulfate conjugates, about 5% unchanged).
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination