neuromuscular blockers

Question 1

Question: What are neuromuscular blockers used for?

Answer 1

Answer: Neuromuscular blockers are used to prevent acetylcholine from acting at the neuromuscular junction, thereby preventing skeletal muscle contractions and causing muscle relaxation.

Question 2

Question: How do skeletal muscles contract?

Answer 2

Answer: Skeletal muscle contraction begins with a signal from the brain, travels as an action potential through upper and lower motor neurons to the neuromuscular junction, where acetylcholine is released, binds to nicotinic receptors on the muscle fiber, causing depolarization and muscle contraction.

Question 3

Question: What are the main parts of the neuromuscular junction?

Answer 3

Answer: The neuromuscular junction consists of the presynaptic membrane (axon terminal), the postsynaptic membrane (motor end-plate of the muscle fiber), and the synaptic cleft (gap between the membranes).

Question 4

Question: How do non-depolarizing neuromuscular blockers work?

Answer 4

Answer: Non-depolarizing neuromuscular blockers compete with acetylcholine for binding to nicotinic receptors but do not open ion channels, leading to decreased depolarization and muscle relaxation.

Question 5

Question: What are some common non-depolarizing neuromuscular blockers?

Answer 5

Answer: Common non-depolarizing neuromuscular blockers include atracurium, vecuronium, rocuronium, pancuronium, and tubocurarine.

Question 6

Question: What are the clinical uses of non-depolarizing neuromuscular blockers?

Answer 6

Answer: Non-depolarizing neuromuscular blockers are used to relax muscles before surgery, during intubation for mechanical ventilation, and as general anesthetics during surgical procedures.

Question 7

Question: What are some side effects of atracurium?

Answer 7

Answer: Atracurium can cause histamine release leading to bronchoconstriction, vasodilation, hypotension, reflex tachycardia, and flushing. It also produces a neurotoxic metabolite called laudanosine, which can cause seizures, especially in individuals with kidney failure.

Question 8

Question: How can the effects of non-depolarizing neuromuscular blockers be reversed?

Answer 8

Answer: The effects of non-depolarizing neuromuscular blockers can be reversed by cholinesterase inhibitors like neostigmine, which increase acetylcholine levels in the synaptic cleft to out-compete the blockers for receptor sites.

Question 9

Question: How do depolarizing neuromuscular blockers work?

Answer 9

Answer: Depolarizing neuromuscular blockers, like succinylcholine, initially mimic acetylcholine and depolarize the motor end-plate, causing temporary muscle contractions (fasciculations), followed by desensitization and muscle relaxation.

Question 10

Question: What are the clinical uses of succinylcholine?

Answer 10

Answer: Succinylcholine is used in emergency settings for rapid intubation and for short surgical procedures.

Question 11

Question: What are some side effects of succinylcholine?

Answer 11

Answer: Succinylcholine can cause hyperkalemia, malignant hyperthermia, and prolonged paralysis in individuals with pseudocholinesterase deficiency.

Question 12

Question: What is the mechanism behind malignant hyperthermia triggered by succinylcholine?

Answer 12

Answer: Malignant hyperthermia is a rare, life-threatening condition triggered by succinylcholine, characterized by extremely high fever and severe muscle rigidity, due to excessive calcium release in muscle cells.