Which statement describes Succinylcholine?

• A. Depolarizing neuromuscular blocker; can cause hyperkalemia.
• B. Non-depolarizing neuromuscular blocker.
• C. Opioid analgesic.
• D. Benzodiazepine.

Answer: (A)

Succinylcholine is a depolarizing neuromuscular blocker. It briefly activates nicotinic acetylcholine receptors at the motor endplate, causing a momentary contraction (fasciculations) followed by a sustained depolarization that renders the muscle unable to contract. This widespread depolarization also opens pathways for potassium to leave muscle cells, so blood potassium can rise, leading to hyperkalemia—especially in people with upregulated extrajunctional receptors from burns, trauma, denervation, or prolonged immobilization, or in those susceptible to malignant hyperthermia. It’s not an opioid or a benzodiazepine, and it works differently from non-depolarizing neuromuscular blockers, which block the receptor without the initial depolarizing fasciculations.