Comparative Pharmacology
Head-to-head clinical analysis: DARVON N W ASA versus PAPA DEINE 3.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N W ASA versus PAPA DEINE 3.
DARVON-N W/ ASA vs PAPA-DEINE #3
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.
Acetaminophen produces analgesia and antipyresis via central COX-2 inhibition and activation of descending serotonergic pathways. Codeine is a prodrug converted to morphine, a mu-opioid receptor agonist, which inhibits ascending pain pathways and alters pain perception.
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, not to exceed 12 tablets in 24 hours. Each tablet contains acetaminophen 300 mg, codeine phosphate 30 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).
Codeine: 2.5-3 hours; Acetaminophen: 2-3 hours; Morphine (active metabolite): 2-3 hours. In hepatic impairment, codeine half-life may extend to 4-6 hours.
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).
Primarily renal (90% as glucuronide conjugates, 10% as morphine, codeine, and norcodeine). Biliary/fecal elimination accounts for <5%.
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination