Comparative Pharmacology
Head-to-head clinical analysis: SUBSYS versus ULTIVA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SUBSYS versus ULTIVA.
SUBSYS vs ULTIVA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Selective mu-opioid receptor agonist with rapid onset and short duration of action; produces analgesia without significant histamine release.
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.
IV bolus: 1 mcg/kg over 30-60 seconds, then continuous IV infusion: 0.25-1 mcg/kg/min for intraoperative analgesia. For general anesthesia induction: 0.5-1 mcg/kg IV bolus; maintenance: 0.25-1 mcg/kg/min IV infusion.
None Documented
None Documented
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.
Terminal elimination half-life is 3-10 minutes (context-sensitive half-time is 3-4 minutes independent of infusion duration due to rapid ester hydrolysis). Clinically, recovery is rapid and predictable even after prolonged infusions, with full recovery within 5-10 minutes of discontinuation.
Primarily renal (~75% as metabolites, <10% unchanged); biliary/fecal excretion of conjugates; ~9% in feces.
Remifentanil is metabolized by non-specific blood and tissue esterases to a virtually inactive metabolite (remifentanil acid, 1/4600 potency). Renal excretion accounts for approximately 90% of the metabolite; fecal elimination is minimal (<5%).
Category C
Category C
Opioid Analgesic
Opioid Analgesic