Neuromuscular Blocking Drugs: Physiology, Pharmacology and Clinical Aspects

Abstract

Neuromuscular blocking agents (NMBAs) were introduced into clinical anaesthetic practice in 1942, by Griffith and Johnson. They changed the practice of anaesthesia and made possible the development of balanced anaesthesia (Griffith and Johnson, Anesthesiology 3:418–420, 1942). The first relaxant was Intoconstrin which was obtained from the plant Chondrodendron tomentosum. In the 50 years that have elapsed, numerous compounds have been synthetised and introduced in clinical practice. As earlier stated by Cecil Gray in 1946: “The road lies open before us, we venture to say we have passed yet another milestone, and the distance to our goal is considerably shortened” (Gray and Halton, Br Med J 2:293–295, 1946). NMBAs are a key component for general anaesthesia. The clinical use of muscle relaxants in routine improves intubating conditions and facilitates perioperative surgical conditions and controlled ventilation. It must be remembered that they should be administered to provide muscular relaxation and that they lack analgesic or anaesthetic effects. Recent publications have highlighted that proper use can improve clinical outcome after surgery. The development of new neuromuscular blocking agents (NMBAs), reversal agents and monitoring techniques leads to improved patient safety and outcome. This chapter reviews the physiology, pharmacology and clinical use of NMBA and reversal agents in clinical practice.