Comparative Pharmacology
Head-to-head clinical analysis: FENTANYL 37 versus FENTANYL CITRATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FENTANYL 37 versus FENTANYL CITRATE.
FENTANYL-37 vs FENTANYL CITRATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fentanyl is a mu-opioid receptor agonist, producing analgesia, sedation, and respiratory depression by activating G-protein coupled opioid receptors in the CNS, leading to inhibition of adenylate cyclase, decreased cAMP, and reduced neurotransmitter release.
Fentanyl is a potent synthetic opioid agonist that primarily acts on mu-opioid receptors in the central nervous system, leading to analgesia, sedation, and euphoria. It also interacts with kappa and delta opioid receptors to a lesser extent. By binding to these receptors, fentanyl inhibits adenylate cyclase, reduces cAMP production, closes voltage-gated calcium channels, and opens inwardly rectifying potassium channels, resulting in hyperpolarization and reduced neurotransmitter release.
For opioid-naive adults, initial dose 50-100 mcg IV/IM every 1-2 hours as needed for pain; transdermal: 12-25 mcg/h applied every 72 hours for opioid-tolerant patients only. For anesthesia: 2-20 mcg/kg IV as part of balanced anesthesia.
Initial adult dose 50-100 mcg IV/IM every 1-2 hours as needed for pain; for anesthesia induction 2-20 mcg/kg IV.
None Documented
None Documented
Terminal elimination half-life: 3–7 hours (prolonged in elderly, hepatic impairment, or with continuous infusion due to context-sensitive half-life up to 300 min).
Terminal elimination half-life: 3-12 hours (mean 4-6 hours in adults). Context: Prolonged with hepatic impairment, elderly, or continuous infusion (context-sensitive half-life increases with infusion duration).
Renal: ~75% (as metabolites, <10% unchanged); Fecal: ~9%; Biliary: minor.
Primarily hepatic metabolism (N-dealkylation to norfentanyl and other metabolites); less than 10% excreted unchanged in urine; approximately 9% excreted in feces via biliary elimination.
Category D/X
Category D/X
Opioid Agonist
Opioid Agonist