Skeletal muscle relaxants are administered at regulated doses to minimize adverse effects. The adverse effects and their severity depend on the type of relaxant used. For example, nondepolarizing blockers have minimal side effects, but directly acting agents may cause general muscle weakness and hepatotoxicity. In contrast, a depolarizing blocker like succinylcholine is associated with severe adverse effects, including cardiac arrhythmia, postoperative muscle pain, prolonged apnea and even respiratory arrest. So, a correct dose of succinylcholine becomes essential, especially for patients with mutated cholinesterases. Because these patients cannot metabolize and eliminate succinylcholine properly, they experience delayed recovery of muscles, such as the diaphragm. As the diaphragm remains paralyzed, it leads to apnea, where sedated patients stop breathing. Additionally, succinylcholine facilitates the release of potassium from intracellular storage. So, it must be avoided in patients with burns, nerve damage or kidney failure who have already suffered rapid potassium loss to prevent cardiac arrest.