Variable designs of clinical trials of neuromuscular blocking agents: an example of studies comparing rocuronium and...

Published clinical trials on neuromuscular blocking (NMB) agents are being reported with large variations in their protocols and conflictiing results may emerge from these differences. Because they have been compared in several clinical trials, the study was focused on rocuronium and vecuronium in order to evaluate whether these NMB agents were compared under homogeneous conditions. MATERIAL/ METHOD: A search was made in PubMed, Embase Drugs and Pharmacology, Cochrane Controlled Trials Register, and Cochrane Database of Systematic Reviews. Studies on the neuromuscular response at the adductor pollicis to an i.v. bolus dose of rocuronium or vecuronium in humans were included. Quality of all reports was assessed by means of the 3-item Jadad et al. scale. Twenty-five studies met our inclusion criteria and all were retrieved.

Randomization was performed in 21 (80.8%) studies. Blinding procedure for drug administration was mentioned in only one study without clarifying the procedure. Induction was most commonly performed with thiopental, followed by propofol. Two studies were performed in children and two in elderly patients. Withdrawals or dropouts were not mentioned in any paper. Electromyography and mechanomyography were the most common monitoring procedures. The time to maximal response, the maximum effect and the time to reach 25% recovery of neuromuscular function were the most used pharmacodynamic parameters.

Clinical trials on neuromuscular blocking agents, e.g. vecuronium versus rocuronium, are being performed with large variability and without following established guidelines.