Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus OPANA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus OPANA.
DARVON vs OPANA
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.
Mu-opioid receptor agonist; produces analgesia by binding to opioid receptors in the CNS, inhibiting ascending pain pathways and altering pain perception.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
5-20 mg orally every 4-6 hours as needed for pain; extended-release tablets: 5 mg orally every 12 hours, titrated up to 20 mg every 12 hours.
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 11-16 hours (mean 14 hours) in adults; prolonged in hepatic impairment (up to 30 hours) and elderly.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Primarily renal (approximately 90% as conjugated metabolites, 10% unchanged); biliary/fecal elimination accounts for <10%.
Category C
Category C
Opioid Analgesic
Opioid Analgesic