Skeletal Muscle Relaxants: Therapeutic Uses

Skeletal muscle relaxants are selected based on the nature and duration of the medical procedure.

For lengthy procedures like abdominal and thoracic surgery, nondepolarizing neuromuscular blocking agents or NMBAs, such as rocuronium, are administered alongside general anesthetics. NMBAs induce muscle paralysis to prevent target organs from contracting under reflex.

In contrast, succinylcholine—a depolarizing NMBA, is used for shorter procedures like laryngoscopy or endotracheal intubation.

Succinylcholine relaxes the laryngeal and pharyngeal muscles and opens airways. This facilitates mechanical ventilation while preventing the patients from choking on fluid or other materials entering the windpipe.

Additionally, both NMBA types reduce chest wall resistance to ensure good ventilation. This benefits critically ill patients suffering from pneumonia, bronchospasm, or atelectasis, where the lungs collapse, allowing only limited gaseous exchange.

Direct acting relaxants like Dantrolene and botulinum toxins treat spastic disorders like cerebral palsy and multiple sclerosis.

Dantrolene is also helpful in treating malignant hyperthermia, while Botulinum toxin injections are routinely used to reduce facial wrinkles.