Terra Pharmaceuticals
Neuromuscular Blocking Drugs- Muscle Relaxants
Muscle relaxants (neuromuscular blocking drugs–NMBDs) adjunct general anesthesia to facilitate endotracheal intubation and mechanical ventilation, and to optimize working conditions for the surgeon by reducing abdominal muscle tone. However, as most NMBD has relatively long half-lives, a small amount of muscle relaxation may persist in the postoperativeperiod (i.e. residual neuromuscular block–RNMB). Consequently, the use of NMBDs is associated with adverse respiratory events after anesthesia. To reduce the risk of RNMB, anaesthesiologist are advised to use neuromuscular monitoring whenever an NMBD is used and exclusively remove the endotracheal tube when the train-of-four-ratio has recovered to at least 90% of baseline values (ie. TOF-ratio≥0.9). If the TOF-ratio is less than 0.9 prior to extubation, reversal agents may be used to speed up the recovery of the neuromuscular block. Currently, two reversal methods exist.
Acetylcholinesterase inhibitors (ACI;eg. neostigmine) are traditionally used to reverse shallow levels of residual neuromuscular block. These drugs temporarily increase the amount of acetylcholine in the neuromuscular junction which results in a competitive antag-onism with the NMBD at the nicotinic acetylcholine receptor. Unfortunately, acetylcholinesterase inhibitors act slowly and are unpredictable in their reversaland they are unsuitable for the reversal of deep neuromuscular block. In addition, they induce systemic cholinergic side-effects which necessitate the co-administration of an anticholinergic drug such as atropine.
In 2008 a new type of reversal agent became available after the clinical approval of the γ-cyclodextrin sugammadex in Europe. Sugammadex reverses neuromuscular block by permanent encapsulation of aminosteroidal NMBDs (eg. rocuronium or vecuronium) molecules in the plasma. Multiple clinical studies have confirmed sugammadex’ability to quickly reverse both shallow and deep levels of aminosteroid neuro-muscular block.
Reference: Expert Opınıon On Drug Safety 2019, VOL. 18, NO. 10, 883–891
