Comparative Pharmacology
Head-to-head clinical analysis: ASTRAMORPH PF versus DARVON.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ASTRAMORPH PF versus DARVON.
ASTRAMORPH PF vs DARVON
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Mu-opioid receptor agonist; produces analgesia, sedation, and euphoria by mimicking endogenous endorphins.
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.
Intravenous: 8-10 mg over 2-5 minutes; may be repeated every 8-12 hours as needed. Oral (immediate release): 10-20 mg every 4-6 hours as needed. Oral (extended release): 10-40 mg every 12 hours.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
None Documented
None Documented
Terminal elimination half-life: 2-4 hours; prolonged in renal impairment (up to 12 hours in anuria) and elderly
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
Renal: 70-80% unchanged; Biliary/Fecal: 10-20% as metabolites
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Category C
Category C
Opioid Analgesic
Opioid Analgesic