Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus OXYCONTIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus OXYCONTIN.
DARVON vs OXYCONTIN
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 the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of oxycodone is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia with oxycodone. Clinically, dosage is titrated to provide adequate analgesia and may be limited by adverse reactions, including respiratory and CNS depression.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
10 mg orally every 12 hours; titrate based on pain severity and prior opioid exposure.
None Documented
None Documented
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
4.5-5.0 hours (immediate-release); controlled-release OXYCONTIN has an apparent half-life of 4.5-8.7 hours. Terminal half-life is ~3.5-4 hours for immediate-release, reflecting context-sensitive elimination.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Primarily renal (90% as metabolites, 10% unchanged). Also biliary/fecal (10%).
Category C
Category C
Opioid Analgesic
Opioid Analgesic