Succinylcholine Chloride: Clinical Use, Mechanism of Action, Administration, Adverse Effects, Contraindications, Monitoring, and Toxicity, June 2003. 1 Succinylcholine Chloride: Clinical Use, Mechanism of Action, Administration, Adverse Effects, Contraindications, Monitoring, and Toxicity Indunil Karunarathna 1 , Asoka Jayawardana 1 , Sau Bandara 1 1. Ministry of Health Sri Lanka. Abstract: Succinylcholine chloride is a short-acting depolarizing neuromuscular blocking agent widely used in medical practice for rapid sequence intubation, surgical procedures, and mechanical ventilation due to its rapid onset and brief duration of action. This comprehensive review discusses the pharmacological mechanisms, clinical applications, administration guidelines, and necessary monitoring to ensure patient safety. Key adverse effects, contraindications, and management of succinylcholine toxicity are also detailed to aid healthcare providers in optimizing its use while minimizing risks. Understanding these critical aspects of succinylcholine chloride enables clinicians to make informed decisions, ensuring effective and safe patient care. Key Words: Succinylcholine Chloride, Neuromuscular Blocking Agent, Rapid Sequence Intubation, Skeletal Muscle Paralysis, Hyperkalemia, Malignant Hyperthermia, Airway Management, Pharmacokinetics, Anesthesia, Toxicity Management Key Points: Mechanism of Action: Succinylcholine works by binding to post-synaptic cholinergic receptors at the motor endplate, causing continuous depolarization, transient fasciculations, and subsequent skeletal muscle paralysis. Administration: Dosage must be calculated based on the patient's total body weight, with careful consideration given to avoiding underdosing or overdosing. Continuous infusion may be necessary for prolonged procedures, monitored with a nerve stimulator. Adverse Effects: Common adverse effects include hyperkalemia, masseter muscle spasms, bradycardia, and increased intraocular pressure. These effects necessitate appropriate precautions and interventions. Contraindications: Contraindications include decreased plasma cholinesterase activity, recent burns or trauma, muscle myopathies, and other specific conditions. Proper evaluation is essential to avoid serious complications. Monitoring: Continuous cardiac monitoring, end-tidal carbon dioxide, and pulse oximetry are crucial. In cases of continuous infusion, a nerve stimulator helps monitor the depth of neuromuscular blockade. Toxicity: Overdosing can lead to prolonged neuromuscular paralysis and respiratory complications. Immediate intervention with airway maintenance and respiratory support is essential until the drug is metabolized. Introduction Succinylcholine chloride is a short-acting depolarizing neuromuscular blocking agent that has received approval from the United States Food and Drug Administration (FDA) for use alongside other sedatives or hypnotics. Its primary mechanism involves blocking the action of acetylcholine (ACh), which results in the disruption of all cholinergic receptors within both the parasympathetic and sympathetic nervous systems. This blocking action facilitates the rapid relaxation of skeletal muscles, making succinylcholine particularly valuable in various medical settings. One of the primary applications of succinylcholine is to expedite rapid endotracheal intubation, a critical procedure in emergency and surgical contexts where securing the airway quickly is essential. Additionally, it plays a significant role in facilitating various surgical procedures and aiding mechanical ventilation by ensuring muscle relaxation. This muscle relaxation is crucial in maintaining a controlled and stable surgical environment and ensuring effective mechanical ventilation. Moreover, succinylcholine is frequently utilized as an adjunct therapy in patients undergoing electroconvulsive therapy (ECT). In this context, it helps control the muscle contractions that are induced by the electrical impulses delivered during the procedure. However, it is important to note that the use of succinylcholine in ECT is