Comparative Pharmacology
Head-to-head clinical analysis: DARVON N versus DURAGESIC 100.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N versus DURAGESIC 100.
DARVON-N vs DURAGESIC-100
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.
Pure opioid agonist that binds to mu-opioid receptors in the CNS, mimicking endogenous endorphins to inhibit pain transmission. Also interacts with kappa and delta receptors. Therapeutic effects include analgesia, sedation, and euphoria.
100 mg orally every 4 hours as needed for pain; maximum 600 mg per day.
Transdermal patch; initial dose based on prior opioid use: for opioid-naive patients, 12 mcg/h every 72 hours; for opioid-tolerant patients, convert using equianalgesic tables; maximum dose 100 mcg/h per patch; apply to non-irritated, non-irradiated skin on chest, back, flank, or upper arm.
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 approximately 20–27 hours after transdermal system removal (range 13–25 hours in healthy adults; prolonged in elderly, hepatic impairment, and cachexia).
Primarily renal (approximately 70% as unchanged drug and glucuronide conjugates); minor biliary/fecal elimination (25-30%).
Renal (primarily as metabolites, <10% unchanged fentanyl); fecal (about 9% of dose).
Category C
Category C
Opioid Analgesic
Opioid Analgesic