Comparative Pharmacology
Head-to-head clinical analysis: DARVON N versus KADIAN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N versus KADIAN.
DARVON-N vs KADIAN
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; modulates pain perception and emotional response to pain.
100 mg orally every 4 hours as needed for pain; maximum 600 mg per day.
20-100 mg orally every 12 hours; titration based on pain severity and prior opioid exposure.
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 of morphine: 2–4 hours; KADIAN extended-release formulation: effective half-life ~12 hours due to prolonged absorption, dosing q12h or q24h
Primarily renal (approximately 70% as unchanged drug and glucuronide conjugates); minor biliary/fecal elimination (25-30%).
Renal: primarily as morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G); ~90% of total elimination is renal, with 10% biliary/fecal
Category C
Category C
Opioid Analgesic
Opioid Analgesic