The Dosage of Muscle Relaxants in Morbidly Obese Patients in Daily Practice – A Narrative Review

Paweł Radkowski,1– 3 Maria Agnieszka Derkaczew,2 Michał Adam Jacewicz,4,5 Dariusz Onichimowski1,2 1Department of Anaesthesiology and Intensive Care, Regional Specialist Hospital in Olsztyn, Olsztyn, Poland; 2Department of Anaesthesiology and Intensive Care, Faculty of Medicine, Collegium Medicum University of Warmia and Mazury in Olsztyn, Olsztyn, Poland; 3Hospital zum Heiligen Geist, Fritzlar, Germany; 4Regional Specialist Hospital in Olsztyn, Olsztyn, Poland; 5Department of Pharmacology and Toxicology, Faculty of Medicine, Collegium Medicum University of Warmia and Mazury in Olsztyn, Olsztyn, PolandCorrespondence: Maria Agnieszka Derkaczew, Department of Anaesthesiology and Intensive Care, Faculty of Medicine, Collegium Medicum University of Warmia and Mazury in Olsztyn, Olsztyn, Poland, Email [email protected]: The prevalence of morbid obesity in today’s population around the world is alarming. Morbid obesity involves substantial changes in body composition and function, which can affect the pharmacodynamics and pharmacokinetics of many drugs. This paper aims to discuss the application of muscle relaxants and their reversing agents in patients with morbid obesity. This work is based both on the available literature and the author’s personal experience. Dosage recommendations for muscle relaxants in morbidly obese patients are as follows: non-depolarizing relaxants like rocuronium, vecuronium, atracurium, and cisatracurium should be based on ideal body weight. Succinylcholine dosage should be adjusted to total body weight with a 200 mg maximum, while mivacurium should also be based on total body weight. Pancuronium is not used due to its long duration. Neostigmine dosing remains uncertain, but some suggest using total body weight. When it comes to Sugammadex opinions of the authors are divided, some indicate that it should be dosed based on ideal body weight, but more recent studies show that it should be based on 40% of corrected body weight.Keywords: muscle relaxants, muscle relaxants reversal agents, succinylcholine, sugammadex, morbid obesity, obese patients