Comparative Pharmacology
Head-to-head clinical analysis: LEVORPHANOL TARTRATE versus SUBSYS.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LEVORPHANOL TARTRATE versus SUBSYS.
LEVORPHANOL TARTRATE vs SUBSYS
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Levorphanol is a potent opioid analgesic that acts as a mu-opioid receptor agonist. It also has NMDA receptor antagonist activity, inhibits norepinephrine and serotonin reuptake, and acts as a sigma receptor agonist, contributing to its analgesic effects and reduced tolerance development.
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.
2 mg orally every 6-8 hours as needed for pain; for opioid-tolerant patients, doses up to 4 mg orally every 6-8 hours may be used. Parenterally: 1-2 mg subcutaneously or intramuscularly every 6-8 hours; may be given intravenously at 0.5-1 mg every 6-8 hours.
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.
None Documented
None Documented
11-16 hours; extended in hepatic impairment (up to 30 hours).
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.
Renal: approximately 30% as unchanged drug and 50% as glucuronide conjugates; fecal: 20% via biliary excretion.
Primarily renal (~75% as metabolites, <10% unchanged); biliary/fecal excretion of conjugates; ~9% in feces.
Category C
Category C
Opioid Analgesic
Opioid Analgesic