Comparative Pharmacology
Head-to-head clinical analysis: DARVON W ASA versus INVAGESIC.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON W ASA versus INVAGESIC.
DARVON W/ ASA vs INVAGESIC
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.
INVAGESIC is a combination of pregabalin, an alpha2-delta ligand that inhibits presynaptic calcium channels to reduce excitatory neurotransmitter release, and meloxicam, a COX-2 selective NSAID that decreases prostaglandin synthesis via cyclooxygenase inhibition.
1 capsule (propoxyphene HCl 65 mg / aspirin 650 mg) orally every 4 hours as needed for pain, not to exceed 6 capsules per day.
Adults: 1-2 tablets (325 mg acetaminophen/5 mg hydrocodone) orally every 4-6 hours as needed for pain, not to exceed 12 tablets per day.
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.
Terminal elimination half-life: 4-6 hours in adults; prolonged to 8-12 hours in elderly or mild renal impairment
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.
Renal: ~70% as unchanged drug; biliary/fecal: ~30% as metabolites
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination