Study Objectives: To determine whether the duration of action of vecuronium is influenced by chronic renal failure.

Design: Prospective clinical comparison.

Setting: Operating room, Hokkaido University Hospital.

Patients: 7 adult ASA physical status II and III patients with impaired renal function undergoing living-related renal transplantation (Group A), 5 adult ASA physical status II and III patients with impaired renal function undergoing elective surgery other than renal transplantation (Group B), and 13 adult ASA physical status I and II patients with normal hepatorenal function undergoing elective surgery (Group C).

Interventions: Anesthesia was induced with thiamylal 5 mg · kg⁻¹ and fentanyl 100 μg IV and maintained with 60% nitrous oxide and 1% isoflurane. An initial dose of vecuronium was administered and patients’ tracheas were intubated.

Measurements: Neuromuscular function was monitored by acceleration of thumb adduction with train-of-four stimulation. Vecuronium 60 μg · kg⁻¹ was administered as the initial dose via a central catheter, and if the first twitch was more than 3% of the control, another dose of vecuronium 20 μg · kg⁻¹ was given as necessary. Both onset time and duration of action until 25% recovery were measured. Plasma vecuronium and its metabolite, 3-desacetyl-vecuronium, levels were measured at onset and at 25% recovery in Groups A and C.

Main Results: The total dose of vecuronium and initial concentration of vecuronium showed no significant difference between Group A and Group C. Duration of action was significantly prolonged in Group A and Group B compared with Group C.

Conclusions: Duration of action of vecuronium is prolonged in patients with end-stage renal failure mainly due to higher sensitivity to vecuronium.