Ketamine
Ketamine. Non-competitive NMDA receptor antagonist (open-channel blocker) + opioid + monoamine reuptake effects. Dissociative anesthetic… Intranasal half-life 2.2 h.
Non-competitive NMDA receptor antagonist (open-channel blocker) + opioid + monoamine reuptake effects. Dissociative anesthetic preserving airway reflexes. Sub-anesthetic IV / intranasal (esketamine) for treatment-resistant depression. Schedule III; recreational misuse signal.
DOSE CORRECTED FROM A PER-KILOGRAM VALUE STORED AS AN ABSOLUTE ONE. The IV block read {"min":0.5,"max":2,"typical":1,"unit":"mg"} — those are mg/kg, not mg, and `doses` admits only absolute mg/g/mcg/IU, so occupancy was being judged at about a seventieth of a real dose. Label verbatim: "Alternatively, administer a dose of 1 to 2 mg/kg at a rate of 0.5 mg/kg/min". At the 70 kg reference that is 70-140 mg, typical 70 mg — ARITHMETIC, mg/kg x 70 kg. Source: Ketalar (ketamine hydrochloride) injection, DailyMed set id 14e8f864-8b8a-4e7e-8439-e510d3107063, v33 published 2026-03-26. The typical takes the LOW end of the label range, which under-doses rather than over-doses the rendered curve. The old row’s 0.5 min had no label support. FOUND BY `occupancy.ts`: nothing reading one field at a time can see this, because every number in the row is individually well-formed. PK: intranasal F 0.45 is verbatim and stands, though from only three subjects; an independent paediatric figure of 0.50 exists (PMID:8881626). The stored 2.5 h matched NO paper — four genuine sources give 2.0, 2.17, 3.1 and 5.2/6.1 h — and is replaced by Domino 1984 (PMID:6488686), eight healthy males on 2.2 mg/kg intravenously, verbatim "elimination (beta t 1/2) = 2.17 hr". THAT SAME PAPER SHOWS DISPOSITION IS THREE-PHASE, so a one-compartment curve is a real simplification here. V 392 L is 5.6 L/kg, the LOWER of the two enantiomer steady-state volumes stated in PMID:34019627 (S 6.6, R 5.6 L/kg) — no racemic human volume appears in any abstract found, and the stored 200 L was roughly half either figure. ka 6 /h dropped and refuted rather than merely unsourced: it implies a seven-minute absorption half-life against an observed nasal peak at about 20 minutes. A prolonged-release oral arm exists in the literature whose 10-11 h half-life is absorption flip-flop and must never reach an immediate-release row.
Pharmacokinetics
- IV — t½ 2.2 h · F 100% · Vd 392 L
- Intranasal — t½ 2.2 h · F 45% · Vd 392 L
Sources: PMID:12516077, PMID:6488686, PMID:34019627, PMID:8881626, PMID:11956671