Comparative Pharmacology
Head-to-head clinical analysis: DURAGESIC 37 versus ULTRAM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DURAGESIC 37 versus ULTRAM.
DURAGESIC-37 vs ULTRAM
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.
Tramadol is a centrally acting synthetic opioid analgesic that binds to μ-opioid receptors and inhibits norepinephrine and serotonin reuptake.
Initial: 25 mcg/hour transdermal patch applied every 72 hours. Titrate based on opioid tolerance. For opioid-naive patients: 12 mcg/hour patch.
50-100 mg orally every 4-6 hours as needed for pain; maximum 400 mg/day (for extended-release: 100 mg once daily, titrated up to 300 mg once daily).
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.
Tramadol: ~6 hours; M1 metabolite (O-desmethyltramadol): ~7 hours; prolonged in renal/hepatic impairment
Primarily renal: 75% as metabolites (mostly norfentanyl) and <10% unchanged drug. Fecal: 9% via biliary elimination.
Renal: ~90% (tramadol and metabolites; conjugated metabolites are major), Fecal: ~10%
Category C
Category C
Opioid Analgesic
Opioid Analgesic