Thiopental
Thiopental. Ultra-short-acting barbiturate — GABA-A positive allosteric modulator. Once the workhorse induction anesthetic; supplanted by propofol.… IV half-life 11 h.
Ultra-short-acting barbiturate — GABA-A positive allosteric modulator. Once the workhorse induction anesthetic; supplanted by propofol. Still used for refractory status epilepticus + execution-protocol contexts. Significant cardiovascular depression at induction doses.
PK: A REAL ACQUITTAL WITH ENTIRELY BROKEN PROVENANCE. The stored pair passes its clearance test to two percent, and NEITHER NUMBER APPEARS IN THE PAPER IT CITED — an EEG study that states no volume and no half-life. Both live in a reference this record already carried: "volume of distribution at steady state 97.5 l ... elimination half-life 11.5 h ... and systemic plasma clearance 0.150 l/min". The stored volume matches NEITHER the steady-state 97.5 NOR the terminal 233, and is almost exactly clearance over the terminal rate — THE CORRECT ONE-COMPARTMENT VOLUME FOR THE STORED HALF-LIFE. SOMEBODY DERIVED IT PROPERLY AND HUNG IT ON THE WRONG PMID; the fix is the citation, not the number. A NARROWER READING OF THE BINDING ACQUITTAL IS ALSO RECORDED: the fraction-unbound note calls saturation excluded, while this record own other reference says "the plasma protein binding of thiopental was CONCENTRATION DEPENDENT ... saturation of binding sites on rapid administration ... may occur" — the linearity finding covers roughly 7-93 ug/mL and the non-linearity appears near 150, which is exactly the post-bolus peak. The acquittal holds for an infusion and not for the induction bolus. DOSE: THE STORED FIGURE WAS THE RAW PER-WEIGHT NUMBER, NOT A DOSE — 3–5 mg/kg induction, entered as flat milligrams. The dose unit enumeration has no weight-based member and the solver never weight-scales a dose, so THE ONLY REPRESENTABLE FORM IS THE SEVENTY-KILOGRAM EQUIVALENT, and that is what this record now carries. I TESTED THE OBJECTION THAT THIS READS A SCHEMA GAP AS A DATA DEFECT AND THE DISTINCTION IS CLEAN: vancomycin stores the seventy-kilogram equivalent of its weight-based regimen and is CORRECT, meropenem is genuinely flat-dosed and is CORRECT, and eleven records store the raw per-weight number and are WRONG BY ROUGHLY SEVENTY-FOLD. Both of my priors on the two correct records were wrong. EFFECT COMPARTMENT: REFUTED AS FITTED, AND THE NUMBER IS RIGHT ANYWAY. The cited paper states that it "used an ASSUMED plasma-effect site rate constant (ke0) of 0.58" — SO THE REGISTRY WAS CITING THE STUDY THAT ASSUMED THE VALUE, NOT ONE THAT MEASURED IT, and an assumed constant carrying no approximation flag is the worst of both. The measurement exists, was made with arterial sampling, and lands within half a percent, corroborated by two further reports; re-pointed, the value can legitimately stay unflagged.
Pharmacokinetics
- IV — t½ 11 h · F 100% · Vd 140 L
Sources: PMID:7235274, PMID:7094508, PMID:6491902