Question

At low dose, which of the following muscle relaxants is most commonly associated with tachycardia?

1) Atracurium
2) Suxamethonium
3) Gallamine
4) Vecuronium

Answer 1

Suxamethonium is the muscle relaxant most commonly associated with tachycardia at low doses due to its initial stimulation of nicotinic receptors leading to an increased heart rate. The answer is option 2.

Step-by-step explanation:

At low doses, the muscle relaxant most commonly associated with tachycardia is suxamethonium (also known as succinylcholine). Suxamethonium acts as a depolarizing neuromuscular blocker. It first stimulates the nicotinic receptors at the neuromuscular junction, causing muscle contraction, before causing prolonged depolarization and subsequent muscle relaxation and paralysis. The initial stimulation can cause an increase in heart rate, or tachycardia, because of its effects on nicotinic receptors in the autonomic ganglia and muscarinic receptors in the heart.

In responding to the multiple-choice question given, suxamethonium is the answer for the muscle relaxant most commonly associated with tachycardia at low doses.