Comparative Pharmacology
Head-to-head clinical analysis: DEMEROL versus FENTORA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DEMEROL versus FENTORA.
DEMEROL vs FENTORA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Meperidine is an opioid agonist that binds to mu-opioid receptors in the central nervous system, mimicking endogenous endorphins to produce analgesia, sedation, and euphoria. It also has additional weak actions at kappa and delta receptors.
Fentanyl is a potent mu-opioid receptor agonist, binding to and activating opioid receptors in the brain and spinal cord, leading to analgesia and sedation.
50-150 mg IM, IV, or SC every 3-4 hours as needed for pain; oral 50-150 mg every 3-4 hours.
For opioid-tolerant adults: 100 mcg (one tablet) placed in buccal cavity; titrate upward in increments of 100 mcg per breakthrough pain episode, with minimum 2-hour interval between doses; maximum 4 doses per day.
None Documented
None Documented
2.5-4 hours; prolonged in hepatic impairment (7-11 hours) and elderly.
Terminal elimination half-life is approximately 2–4 hours in adults, but can range from 2 to 6 hours depending on hepatic clearance. In elderly or hepatically impaired patients, half-life may be prolonged. The rapid initial decline is due to redistribution, and the terminal phase reflects slow elimination from deep compartments.
Renal (90% as metabolites and unchanged drug; ~5% unchanged) and biliary/fecal (minor).
Primarily renal: Approximately 75% of the dose is excreted in urine as metabolites (mostly norfentanyl, despropionylfentanyl, and hydroxyfentanyl), with less than 7% as unchanged fentanyl. Fecal elimination accounts for about 9%.
Category C
Category C
Opioid Analgesic
Opioid Analgesic