Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus OXAYDO.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus OXAYDO.
DARVON vs OXAYDO
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Propoxyphene is a mu-opioid receptor agonist that inhibits ascending pain pathways by binding to opioid receptors in the CNS, altering pain perception. It also has weak local anesthetic effects.
Oxycodone is a full opioid agonist with relative selectivity for mu-opioid receptors, although it can bind to kappa-opioid receptors at higher doses. The principal therapeutic action of oxycodone is analgesia. Like all full opioid agonists, there is no ceiling effect to analgesia for oxycodone.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
Oral, 5-10 mg every 4-6 hours as needed for pain; maximum 60 mg per day.
None Documented
None Documented
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
Terminal elimination half-life is 3.5-5.5 hours for immediate-release oxycodone; clinically dose every 4-6 hours for sustained analgesia.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Primarily renal as unchanged drug and metabolites; ~90% excreted in urine (approx 10% unchanged oxycodone, rest as noroxycodone and oxymorphone conjugates) and <10% in feces via biliary elimination.
Category C
Category C
Opioid Analgesic
Opioid Analgesic