COMPARISON OF CUMULATIVE AND SINGLE BOLUS DOSE TECHNIQUES FOR DETERMINING THE POTENCY OF VECURONIUM

Abstract

The potency of vecuronium was determined using single bolus dose administrations of 10–50 μg kg⁻¹in 28 patients anaesthetized with thiopentone, nitrous oxide, oxygen and fentanyl. The results were compared with those previously obtained using a cumulative dose technique in a comparable group of 10 patients. The 50% and 95% blocking doses (ED₅₀and ED₉₅) of vecuronium were found to be 23.1 and 39.6 μg kg⁻¹, respectively. These were significantly lower than the 30.5 and 56.7μg kg⁻¹ obtained previously using the cumulative dose technique. We recommend the use of single bolus dose method of determining potency for relatively shorter-acting drugs like vecuronium.