Comparative Pharmacology
Head-to-head clinical analysis: DURAGESIC 37 versus LEVORPHANOL TARTRATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DURAGESIC 37 versus LEVORPHANOL TARTRATE.
DURAGESIC-37 vs LEVORPHANOL TARTRATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fentanyl binds to mu-opioid receptors, activating G-protein coupled receptor signaling, leading to inhibition of adenylate cyclase, decreased cAMP production, and modulation of ion channels (increased potassium efflux, decreased calcium influx). This results in reduced neuronal excitability, inhibition of nociceptive transmission, and altered pain perception. Additionally, fentanyl may interact with other opioid receptors (kappa, delta) with lower affinity.
Levorphanol is a potent opioid analgesic that acts as a mu-opioid receptor agonist. It also has NMDA receptor antagonist activity, inhibits norepinephrine and serotonin reuptake, and acts as a sigma receptor agonist, contributing to its analgesic effects and reduced tolerance development.
Initial: 25 mcg/hour transdermal patch applied every 72 hours. Titrate based on opioid tolerance. For opioid-naive patients: 12 mcg/hour patch.
2 mg orally every 6-8 hours as needed for pain; for opioid-tolerant patients, doses up to 4 mg orally every 6-8 hours may be used. Parenterally: 1-2 mg subcutaneously or intramuscularly every 6-8 hours; may be given intravenously at 0.5-1 mg every 6-8 hours.
None Documented
None Documented
Terminal elimination half-life 20-27 hours (range 13-42 h) after transdermal removal; due to continuous absorption from skin depot, effective half-life is longer during patch wear.
11-16 hours; extended in hepatic impairment (up to 30 hours).
Primarily renal: 75% as metabolites (mostly norfentanyl) and <10% unchanged drug. Fecal: 9% via biliary elimination.
Renal: approximately 30% as unchanged drug and 50% as glucuronide conjugates; fecal: 20% via biliary excretion.
Category C
Category C
Opioid Analgesic
Opioid Analgesic