Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus STADOL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus STADOL.
DARVON vs STADOL
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.
Partial agonist at mu-opioid receptors and agonist at kappa-opioid receptors in the CNS, altering pain perception and emotional response to pain.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
Butorphanol tartrate 1-2 mg IV or IM every 3-4 hours as needed for pain; alternatively, 0.5-1 mg IV every 3-4 hours. For nasal spray: 1 mg (one spray) in one nostril, may repeat in 60-90 minutes if needed; then 1 mg every 3-4 hours as needed.
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: 2.5-4 hours; clinically, prolonged in hepatic impairment (up to 10-12 hours) and elderly
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Renal: 85-90% as unchanged drug and metabolites (primarily as glucuronide conjugates); Fecal: <10%; Biliary: minimal
Category C
Category C
Opioid Analgesic
Opioid Analgesic