Comparative Pharmacology
Head-to-head clinical analysis: DARVON W ASA versus ROXICET 5 500.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON W ASA versus ROXICET 5 500.
DARVON W/ ASA vs ROXICET 5/500
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination analgesic: propoxyphene is a weak opioid agonist binding to mu-opioid receptors, inhibiting ascending pain pathways; aspirin irreversibly inhibits cyclooxygenase-1 and -2, reducing prostaglandin synthesis.
Oxycodone is a full opioid agonist that binds to mu-opioid receptors in the CNS, inhibiting ascending pain pathways and altering pain perception. Acetaminophen inhibits cyclooxygenase (COX) enzymes, primarily in the CNS, reducing prostaglandin synthesis and producing analgesic and antipyretic effects.
1 capsule (propoxyphene HCl 65 mg / aspirin 650 mg) orally every 4 hours as needed for pain, not to exceed 6 capsules per day.
1-2 tablets (5-10 mg oxycodone / 325-650 mg acetaminophen) orally every 4-6 hours as needed for pain; maximum 12 tablets per day (60 mg oxycodone / 6000 mg acetaminophen) in 24 hours.
None Documented
None Documented
Propoxyphene terminal half-life is 6–12 hours (mean 8 h) in healthy adults; prolonged in hepatic impairment or elderly due to reduced metabolism. Aspirin half-life is 15–20 minutes due to rapid hydrolysis to salicylate.
Oxycodone: 3-5 hours (immediate-release); Acetaminophen: 2-3 hours. In hepatic impairment, oxycodone half-life prolonged (up to 12-15 hours).
Renal elimination of propoxyphene and its metabolites accounts for ~70% of a dose, with ~20% excreted unchanged in urine; biliary/fecal elimination accounts for ~10%; aspirin is renally excreted as salicylate and its conjugates.
Oxycodone: primarily hepatic metabolism to noroxycodone, oxymorphone, and conjugates; renal elimination of metabolites (about 60-87% as unchanged and metabolites), fecal < 10%. Acetaminophen: renal elimination of conjugates (90-100%), <5% unchanged.
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination