Comparative Pharmacology
Head-to-head clinical analysis: DARVON N W ASA versus ROXICET.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N W ASA versus ROXICET.
DARVON-N W/ ASA vs ROXICET
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.
Roxicet is a combination of oxycodone, a full mu-opioid receptor agonist, and acetaminophen, which inhibits cyclooxygenase (COX) enzymes, primarily in the central nervous system, to reduce pain perception and fever.
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 (oxycodone 5-10 mg/acetaminophen 325-650 mg) orally every 4-6 hours as needed for pain; maximum acetaminophen 4000 mg/day (3000 mg/day in high-risk patients).
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 (immediate-release); prolonged in hepatic/renal impairment. Acetaminophen: 2-3 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% unchanged). Biliary/fecal excretion is minor (<5%).
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination