Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus MS CONTIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus MS CONTIN.
DARVON vs MS CONTIN
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; binds to mu-opioid receptors in the CNS, modulating 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.
Oral: 15-30 mg every 8-12 hours; adjust based on pain severity and prior opioid use. Extended-release tablets must be swallowed whole; do not crush or chew. For opioid-naïve patients, start at 15 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: 11-13 hours (range 8-24 hours). In elderly or hepatic impairment, half-life may be prolonged; acute dosing half-life ~2-4 hours.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Renal: ~90% (mostly as morphine-3-glucuronide and morphine-6-glucuronide, with ~10% as unchanged morphine); Fecal: <10%
Category C
Category C
Opioid Analgesic
Opioid Analgesic