Comparative Pharmacology
Head-to-head clinical analysis: ALFENTANIL versus SUBSYS.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ALFENTANIL versus SUBSYS.
ALFENTANIL vs SUBSYS
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Alfentanil is a potent, short-acting synthetic opioid analgesic that primarily acts as a mu-opioid receptor agonist. It binds to mu-opioid receptors in the central nervous system, leading to G-protein coupled activation of inwardly rectifying potassium channels and inhibition of voltage-gated calcium channels, resulting in hyperpolarization and reduced neurotransmitter release. This produces analgesia, sedation, and respiratory depression.
SUBSYS (fentanyl) is a mu-opioid receptor agonist that produces analgesia by mimicking endogenous opioids, increasing potassium efflux and reducing calcium influx, thereby inhibiting neuronal transmission of pain signals.
Initial IV bolus of 5-20 mcg/kg; maintenance infusion of 0.5-1.5 mcg/kg/min; incremental boluses of 5-10 mcg/kg as needed. Induction of anesthesia: 50-100 mcg/kg IV.
SUBSYS (fentanyl buccal soluble film) is indicated for breakthrough pain in opioid-tolerant patients. Initial dose: 100 mcg (one 100 mcg film) placed on the inner cheek, allowed to dissolve over 15-25 minutes; may repeat once after 30 minutes if pain not relieved. Titrate to effective dose (200, 400, 600, 800, 1200, 1600 mcg). Maximum: 4 doses per day. No more than 2 doses per breakthrough pain episode. Wait at least 2 hours before treating next episode.
Clinical Note
moderateAlfentanil + Torasemide
"The risk or severity of adverse effects can be increased when Alfentanil is combined with Torasemide."
Clinical Note
moderateAlfentanil + Etacrynic acid
"The risk or severity of adverse effects can be increased when Alfentanil is combined with Etacrynic acid."
Clinical Note
moderateAlfentanil + Furosemide
"The risk or severity of adverse effects can be increased when Alfentanil is combined with Furosemide."
Clinical Note
moderateAlfentanil + Bumetanide
None Documented
None Documented
Terminal elimination half-life: 90–111 minutes (1.5–1.85 hours). Clinically, context-sensitive half-time is short (~40 min after 3-hour infusion) due to rapid redistribution and metabolism.
Terminal half-life 2–4 hours (single dose); prolonged to 7–15 hours in hepatic/renal impairment; clinical context: necessitates q4–6h dosing for chronic pain.
Primarily hepatic metabolism via CYP3A4; <1% excreted unchanged in urine; metabolites (mainly noralfentanil) excreted renally. Biliary/fecal excretion of metabolites accounts for ~30%.
Primarily renal (~75% as metabolites, <10% unchanged); biliary/fecal excretion of conjugates; ~9% in feces.
Category C
Category C
Opioid Analgesic
Opioid Analgesic
"The risk or severity of adverse effects can be increased when Alfentanil is combined with Bumetanide."