Figure 13-21 Metabolism of vecuronium as it occurs in the liver. About 30% to 40% of an injected dose is deacetylated at the 3- and 17-positions. The major metabolite is 3-OH vecuronium (red arrow). The metabolites are excreted in urine and bile. The 3-OH metabolite is nearly as potent as the parent compound and is probably cleared from blood at a rate slightly slower than that of vecuronium. (Redrawn from Agoston S, Seyr M, Khuenl-Brady KS, et al: Use of neuromuscular blocking agents in the intensive care unit. Anesthesiol Clin North Am 11:345, 1993.)