Skeletal Muscle Relaxants

Question 1

Neuromuscular blocking agents=skeletal muscle relaxants=paralytics

Answer 1

-NMBAs weaken or paralyze muscles to prevent body movement by interfering with Acetylcholine (Ach) at the neuromuscular junction (NJ)

Question 2

2 Types of NMBAs

Answer 2

Depolarizing Agents and Nondepolarizing Agents

Question 3

Depolarizing Agents

Answer 3

→ bind to Ach and cause sustained postsynaptic membrane depolarization (flaccid muscles)

Question 4

Succinylcholine (DA medication)

Answer 4

• ultra short action and duration (60-90 second onset; 10-15 minute duration)
• cannot be reversed
• subsequent doses not effective
• primarily used just prior to intubation

Question 5

Severe side effects of Succinylcholine

Answer 5

• tachycardia and hypertension
• vagal responses
• histamine release (bronchospasm)
• hyperkalemia (arrythmias and cardiac arrest)

Question 6

Nondepolarizing Agents

Answer 6

→ compete with Ach for binding at the receptors and therefore block the depolarizing effects of Ach (prevent muscle contraction)
-Block Ach receptors without activating them

Question 7

Adverse Effects of Nondepolarizing Agents

Answer 7

• tachycardia and hypertension
• histamine release (bronchospasm)
• vagal responses
• inadequate ventilatory function

Question 8

Reversal Agents

Answer 8

→ Neostigmine (a cholinesterase inhibitor), usually given with Atropine to prevent severe bradycardia

Question 9

Clinical use of NMBAs

Answer 9

• prior to endotracheal intubation
• muscle relaxation during surgery
• to enhance patient-ventilator synchrony
• NMBAs cause muscle paralysis without affecting consciousness or the perception of pain