Atracurium
Atracurium. Benzylisoquinolinium non-depolarizing neuromuscular blocker — competitive nicotinic ACh antagonist. Cleared by Hofmann elimination +… IV half-life 0.3 h.
Benzylisoquinolinium non-depolarizing neuromuscular blocker — competitive nicotinic ACh antagonist. Cleared by Hofmann elimination + ester hydrolysis (organ-independent), making it useful in renal/hepatic failure. Histamine release at high IV bolus.
PK: THE CLEANEST PK ROW IN THIS AUDIT, ATTACHED TO THE WRONG PAPER. The cited study reports "volume of distribution and plasma clearance were 217 ml/kg and 550 ml/min" and a half-life "averaged 22 minutes" — none of which is what the record stores. The stored values are verbatim in a paper it never cited: "19.9 min (+/- 0.6) for the elimination half-life (T1/2 beta), 5.5 ml min-1 kg-1 (+/- 0.2) for total clearance (Cl) and 157 ml kg-1 (+/- 7) for total distribution VOLUME (Varea)". AND IT IS THE TEXTBOOK-CORRECT PAIRING — a Varea, NOT a Vss, married to a terminal half-life is exactly what a one-compartment exposure model needs — so the implied clearance reproduces that paper own stated figure to two significant figures. Fix the citation and touch nothing else. DOSE: THE STORED FIGURE WAS THE RAW PER-WEIGHT NUMBER, NOT A DOSE — 0.4–0.5 mg/kg intubating, 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. OCCUPANCY: THE THIRD COMPENSATING-ERROR PAIR AND THE MOST INSTRUCTIVE. Two independent errors of roughly sixty and seventy fold ran in opposite directions and cancelled: the dose was the raw per-kilogram intubating figure, and the potency term was a patch-clamp measurement in DENERVATED MOUSE skeletal muscle where THIS RECORD OWN PHARMACOKINETIC CITATION CONTAINS THE HUMAN IN-VIVO VALUE. Together they rendered an occupancy of 51 percent, which looks entirely plausible. FIXING THE DOSE ALONE DRIVES IT TO 98.6 PERCENT AND SATURATES; FIXING THE POTENCY ALONE DROPS IT TO 3.2 AND NULLS. BOTH TOGETHER — with the sigmoidicity factor from the same sentence — GIVE 70 PERCENT, WHICH IS CORRECT. This is why an audit that fixes one defect at a time is not merely slower but can be actively harmful.
Pharmacokinetics
- IV — t½ 20 min · F 100% · Vd 11 L
Sources: PMID:3674472, PMID:7486041, PMID:6687550