Butorphanol
Butorphanol. Mixed κ-opioid agonist + partial μ agonist — analgesia with ceiling on respiratory depression. Intranasal formulation (Stadol… Intranasal half-life 6.3 h.
Mixed κ-opioid agonist + partial μ agonist — analgesia with ceiling on respiratory depression. Intranasal formulation (Stadol NS) used for migraine + acute pain; abuse potential led to scheduling.
PK: THE INTRAVENOUS ROW VERIFIES AND ITS VOLUME IS A TRUE Vss — "The mean CLT and Vss were 121 l.h-1 and 791 l ... for the intravenous treatment" — so pairing it with the nasal bioavailability is CORRECT, the class-6 case the brief warned about. The nasal half-life of 6 h matched neither arm of its own paper, which reports "5.95, 6.28, and 5.77 h, for treatments A, B, and C"; the transnasal arm value is now carried. F 0.7 was RIGHT WITH THE WRONG CITATION: the cited study reports 72% and was run in RHINITIS PATIENTS, chosen because nasal pathology might alter nasal absorption, while 0.70 is verbatim in a healthy-volunteer study. ka 3 is unsourced; the only absorption datum is a mean absorption time of 0.23 h, implying 4.35. Its intramuscular route is declared with no parameters and is removed. BOTH OPIOID OCCUPANCY ROWS ARE REMOVED — see the receptor block.
Pharmacokinetics
- IV — t½ 6 h · F 100% · Vd 791 L
- Intranasal — t½ 6.3 h · F 70% · Vd 791 L
Sources: PMID:18467078, PMID:8157043, PMID:18674902, PMID:8218955