Administration of metoclopramide by infusion or bolus does not affect the incidence of drug-induced akathisia.

The study aims to determine if slow intravenous infusion of metoclopramide reduces the incidence of acute drug-induced akathisia (DIA) compared with intravenous bolus. A prospective, double-blind, double dummy trial of adult patients requiring intravenous metoclopramide in the ED. Participants were randomised to receive either: metoclopramide 20 mg as a bolus and normal saline infusion over 15 min, or normal saline bolus and metoclopramide 20 mg infused over 15 min. Patients were assessed for DIA using the Prince Henry Akathisia Rating Scale before treatment was commenced and at 20, 40 and 60 min post. Nausea was assessed with a visual analog scale. Of 210 participants assessed for eligibility, 206 were randomised and 205 were included in the final analysis. Participant characteristics and indication for metoclopramide were well matched between the treatment groups. Overall, incidence of DIA was 26 out of 205 participants (12.68%, 95% confidence interval [CI] 8.09-17.3). DIA occurred in 11 out of 103 (10.68%, 95% CI 4.61-16.74%) in the bolus group, and in 15 out of 102 (14.71%, 95% CI 7.71-21.70%) in the infusion group (P = 0.67). Severe DIA occurred in six patients in each group. The mean age of patients experiencing DIA was 34 years (interquartile range 29-40) and 42 years (interquartile range 40-45) in those without akathisia (P = 0.04). Nausea reduction was equivalent in both groups. The incidence of DIA and reduction in nausea is unaffected by the rate of administration of intravenous metoclopramide 20 mg.