Comparative Pharmacology
Head-to-head clinical analysis: DARVON N versus MS CONTIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N versus MS CONTIN.
DARVON-N vs MS CONTIN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Propoxyphene is a weak mu-opioid receptor agonist that produces analgesia by binding to opioid receptors in the central nervous system, altering the perception of and response to pain. Its metabolite norpropoxyphene has local anesthetic and sodium channel blocking effects, which may contribute to cardiac toxicity.
Mu-opioid receptor agonist; binds to mu-opioid receptors in the CNS, modulating pain perception and emotional response to pain.
100 mg orally every 4 hours as needed for pain; maximum 600 mg per 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
Propoxyphene: 6-12 hours; norpropoxyphene: 30-36 hours. Accumulation of norpropoxyphene on repeated dosing increases 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 renal (approximately 70% as unchanged drug and glucuronide conjugates); minor biliary/fecal elimination (25-30%).
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