Comparative Pharmacology
Head-to-head clinical analysis: BUTORPHANOL TARTRATE versus DARVON.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BUTORPHANOL TARTRATE versus DARVON.
BUTORPHANOL TARTRATE vs DARVON
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Butorphanol tartrate is a mixed agonist-antagonist opioid analgesic that exerts its effects primarily through partial agonism at the mu-opioid receptor and full agonism at the kappa-opioid receptor. This results in analgesia with a ceiling effect for respiratory depression. It also has weak antagonistic activity at the mu receptor.
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.
1-2 mg intravenously or intramuscularly every 3-4 hours as needed; alternatively, 1-2 mg intranasally as a single dose (for migraine, may repeat after 60 minutes). For patient-controlled analgesia (PCA): 0.5-1 mg intravenous bolus with lockout interval of 10-15 minutes. Epidural: 0.5-2 mg as a single dose.
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 is 2.5-3.5 hours (mean ~3 hours) in adults; prolonged in hepatic impairment (up to 5-6 hours) and renal impairment (variable, may increase).
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
Primarily hepatic metabolism to inactive metabolites; renal excretion accounts for approximately 70-80% of elimination (mostly metabolites), with 15-20% via feces (biliary). Less than 5% excreted unchanged in urine.
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