Pharmacodynamic interaction between pantoprazole and vecuronium at neuromuscular junction

1 The effect of pantoprazole on vecuronium-induced neuromuscular blockade in in vivo has not been clearly defined. In this study, we demonstrate that chronic administration, but not acute administration, of pantoprazole alters the pattern of vecuronium-induced neuromuscular blockade.

2 This study was designed to evaluate the effect of acute and chronic administration of pantoprazole on vecuronium-induced neuromuscular blockade using the rat in vivo sciatic nerve-stimulated gastrocnemius preparation.

3 Vecuronium was administered as a slow intravenous infusion (29.41 μg kg⁻¹ min⁻¹) until the gastrocnemius twitch response to sciatic nerve stimulation was completely abolished. The effect of acute (single dose, i.v.) and chronic administration (per oral for 21 days) of pantoprazole (3.64 mg kg⁻¹) on vecuronium-induced blockade was assessed by comparing ED₅₀ values, time required for 50% block, ED₉₅ values, block duration and percentage of recovery with respect to control.

4 Acute administration of pantoprazole had no significant effect on any parameter of vecuronium-induced neuromuscular blockade. Chronic administration of pantoprazole significantly reduced vecuronium ED₅₀ value, time for 50% block, ED₉₅ value and percentage recovery from blockade compared with the control group (P < 0.05). Reduction in the duration of vecuronium-induced blockade was not significantly affected by chronic treatment with pantoprazole compared with control.

5 On chronic administration, pantoprazole may produce earlier block, quick relaxation and reduces the recovery of vecuronium without affecting its duration of action.