Comparative Pharmacology
Head-to-head clinical analysis: FENTANYL 62 versus WESTADONE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FENTANYL 62 versus WESTADONE.
FENTANYL-62 vs WESTADONE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fentanyl is a synthetic opioid agonist primarily acting on mu-opioid receptors in the central nervous system, leading to analgesia, sedation, and respiratory depression.
Mu-opioid receptor agonist; also acts as an NMDA receptor antagonist and inhibits serotonin and norepinephrine reuptake.
For analgesia: 50-100 mcg IV/IM every 1-2 hours as needed. For anesthesia: 2-50 mcg/kg IV. For PCA: 10-20 mcg IV with 5-10 min lockout. Transdermal: 12-100 mcg/h patch every 72 hours; start at 25 mcg/h in opioid-naive patients.
Oral: 2.5-10 mg every 4-6 hours as needed for pain; maximum 40 mg per day.
None Documented
None Documented
3–7 hours (terminal elimination half-life; prolonged in elderly, hepatic impairment, or with continuous infusion due to redistribution).
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.
Renal (primarily as metabolites, <10% unchanged; ~75% total metabolites in urine), fecal (~9% total metabolites).
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