Increased Sensitivity to Vecuronium in Patients with Chronic Renal Failure

The sensitivity of patients with chronic renal failure (CRF) to vecuronium was examined by determining plasma concentration-effect relationships at 85% and 60% block during infusion. The log-logit vecuronium plasma concentration-effect curves were shifted to the left in 9 patients with CRF compared with 6 control subjects (p < 0.001), indicating increased sensitivity in patients with CRF. The 3-desacetyl metabolite of vecuronium was detected in plasma in 1 patient with CRF, whereas it was present in all control patients (p = 0.0014). Some guanidino compounds have been reported to increase acetylcholine release. The relationship between serum levels of guanidino compounds and the sensitivity to vecuronium was studied and guanidino-succinic acid, guanidine, methyl-guanidine and creatinine levels were elevated in patients with CRF. Urea and guanidine levels correlated with patients’ sensitivity to vecuronium (r = −0.64 and r = −0.66, respectively; p < 0.01)