Comparative Pharmacology
Head-to-head clinical analysis: FENTANYL 87 versus WESTADONE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FENTANYL 87 versus WESTADONE.
FENTANYL-87 vs WESTADONE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fentanyl is a synthetic opioid that primarily acts as a mu-opioid receptor agonist, inhibiting adenylate cyclase, decreasing cAMP production, and modulating ion channels (calcium, potassium) to reduce neurotransmitter release and neuronal excitability.
Mu-opioid receptor agonist; also acts as an NMDA receptor antagonist and inhibits serotonin and norepinephrine reuptake.
IV: 0.5-2 mcg/kg as a bolus; continuous infusion: 0.7-10 mcg/kg/hr. Transdermal: 25-100 mcg/h every 72 hours. Transmucosal (buccal or lozenge): 200-1600 mcg as a single dose.
Oral: 2.5-10 mg every 4-6 hours as needed for pain; maximum 40 mg per day.
None Documented
None Documented
Terminal elimination half-life is approximately 3–12 hours (mean 7 hours) in adults; prolonged to up to 20–30 hours in elderly, critically ill, or patients with hepatic impairment. Context-sensitive half-life increases with infusion duration.
Terminal elimination half-life: 15-60 hours (mean ~24 hours). Clinical context: Prolonged half-life supports once-daily dosing in opioid maintenance; accumulation occurs with repeated dosing due to long half-life.
Primarily hepatic metabolism (>90%) to norfentanyl and other inactive metabolites; renal excretion of metabolites accounts for approximately 75% of total elimination, with about 9% excreted unchanged in urine. Fecal excretion is minimal (<9%).
Primarily renal (40-50% as unchanged methadone and its metabolites, 15-20% as metadone-N-oxide), biliary/fecal (5-10%).
Category D/X
Category C
Opioid Agonist
Opioid Agonist