Chapter 16 - Neuromuscular and Ganglionic Blocking Agents

Question 1

Neuromuscular Blocking Agents - def

Answer 1

Block Nicotinic M receptors. Cause muscle relaxation.

Question 2

Neuromuscular Blocking Agents - commonly used during…

Answer 2

surgery, endotracheal intubation, mechanical ventilation, diagnostic procedures, diagnostic procedures.

Question 3

Ganglionic Blocking Agents - def

Answer 3

block nicotinic n receptors in autonomic ganglia.

Question 4

Steps in Muscle Contraction - 3

Answer 4

3 - Polarization (+ outside and - inside), Depolarization (Na+ diffuses in to make inside +), Repolarization (K+ diffuses out to make inside).

Question 5

Neuromuscular blocking agents are classified according to Mechanism of action…… 2

Answer 5

Non-depolarizing and Depolarizing.

Question 6

neuromuscular blocking agents are also classified according to Time course of action … 4

Answer 6

Long acting, Intermediate acting, Short acting, ultra-short acting.

Question 7

Neuromuscular Blocking Agents - Nondepolarizing Drug

Answer 7

Tubocurarine (prototype) - however, it’s not used in the USA anymore.
Doxacurium, Atracurium, Mivacurium.

Question 8

Non-depolarizing neuromuscular blocking drugs -

Answer 8

Succinylcholine

Question 9

Tubocurarine - causes…

Answer 9

paralysis of skeletal muscle. Also carries a plus charge.

Question 10

Tubocurarine - mechanism of action.

Answer 10

competes with ACH for binding to nicotinic M receptors on motor end plate (does NOT mimic but block Ach) therefore no muscle contraction.

Question 11

Therapeutic uses of Tubocurarine -

Answer 11

muscle relaxation and hypotension.

Question 12

Tubocurarine - adverse effects.

Answer 12

Respiratory arrest, cardiovascular effects.

Question 13

Tubocurarine - drug interactions.

Answer 13

General anesthetics can enhance action, antibiotics can intensify response (tetracycline, gentamicin) AChE inhibitors can decrease effects of tubocurarine.)

Question 14

Tubocurarine - overdose has 3 major effects.

Answer 14

Prolonged apnea, massive histamine release, and cardiovascular collapse.

Question 15

Tobocurarine - Dosage & Administration

Answer 15

IV administration, only by specially trained clinicians, 20 units/ml solution. repeated doses.

Question 16

Succinylcholine -

Answer 16

only depolarizing neuromuscular blocker in clinical use. Very short acting, binds to nicotinic m receptors on motor end plate and causes depolarization.

Question 17

Time course of action for Neuromuscular blocking agents and drugs in that time.

Answer 17

Long acting - doxocurium, metocurine.
Intermediate acting - atracurium, pancuronium.
Short acting - mivacurium.
Ultra short acting - succinylcholine

Question 18

Ganglionic blocking agents - Block…

Answer 18

nicotinic n in autonomic ganglia. They lack selectivity; so that means limited application.

Question 19

Ganglionic blocking agents are used for __

Answer 19

essential hypertension (hypertension with cause unknown.)

Question 20

Side effects of ganglionic blocking agents -

Answer 20

antimuscarinic - parasympathetic blockade, hypotension - sympathetic blockade.

Question 21

Mecamylamine (inversine) - only ___ blocker available in the US.

Answer 21

ganglionic.

Question 22

Mecamylamine - what does it do?

Answer 22

interrupts impulse through ganglia of autonomic nervous system.
Stops all autonomic control of organs.
Competes with ACh for binding to nicotinic n receptors of sympathetic and parasympathetic systems.

Question 23

Mecamylamine - pharmacokinetics -

Answer 23

well absorbed following oral administration. Effect within 2 hours and lasts 12 hours. Lipid soluble, eliminated through urine.

Question 24

What’s the therapeutic use of mecamylamine?

Answer 24

For essential hypertension! (hypertension with an unknown cause.)

Question 25

Mecamylamine - adverse reactions.

Answer 25

Antimuscarinic effects - blurred vision, photophobia, etc.
Hypotension
CNS effects - tremors, convulsions, etc.