Pharm: Ganglionic Blockers

Question 0

Trimethaphan

Answer 0

MOA: nicotinic receptor blocker

Indications: hypertensive emergency, dissecting aortic aneurysm

Question 1

What is the general MOA of ganglionic blocker?

Answer 1

Nicotinic receptor blockers in peripheral ganglia.

Question 2

Mecamylamine

Answer 2

MOA: nicotinic receptor blocker

Indications: adjunctive therapy to nicotine patch for smoking cessation.

Question 3

What is autonomic dysreflexia and how ganglionic blockers treat it?

Answer 3

AD is a reaction of the autonomic nervous system to OVERstimulation. The ganglionic blockers treat this overstimulation by blocking the ACh receptors.

Question 4

What effect does Myasthenia Gravis, Lambert Eaton, and advanced age have on the dosing of neuromuscular blockers?

Answer 4

All cases result in a decrease in the dose to acheive the desired effect.
MG: there are antibodies already blocker ACh receptors; therefore not as much of a NM blocker is needed

LE: not as much ACh is released by the presynaptic neurons; so not as much NM blocker is needed

Advanced Age: decreases the clearance rate of the drug so the dose should be smaller

Question 5

What are the 2 MOAs of non-depolarizing NM blockers?

Answer 5

1. Compete with ACh at the nicotinic receptor when in small doses
2. Enter the pore of the ion channel and decrease sensitivity to neostigmine or edrophonium in large doses

Question 6

Name 4 drug classes that enhance the action of the NM blockers.

Answer 6

1. Inhaled anesthetics (lidocaine, isoflurane)
2. Aminoglycosides (gentamicin, streptomycin)
3. Tetracyclines
4. Calcium Channel Blockers (verapamil, nifedipine)

Question 7

What is unique about the metabolism of cisatracurium?

Answer 7

Undergoes Hoffman degeneration: spontaneous metabolism that doesn’t require enzymes.

Question 8

Which drug is used as a paralytic agent to produce muscle relaxation during surgery and tracheal intubation in patients with impaired renal and hepatic function?

Answer 8

Cisatracurium

Question 9

Which 4 NM blockers have intermediate duration of action and are used for muscle relaxation and sedation?

Answer 9

Atracurium, cisatracurium, vecuronium, rocuronium

Question 10

Which 2 NM blockers have a long duration of action?

Answer 10

Doxacurium, pancuronium

Question 11

Name the drug that can reverse the action of steroid NM blockers.

Answer 11

Sugammadex

Question 12

Succinylcholine

Answer 12

MOA: depolarizing NM blocker

Indications: airway intubation (preferred choice)

AE: muscle fasciculations, may cause apnea in large doses or patients with atypical cholinesterases, malignant hyperthermia

Question 13

What is the treatment for succinylcholine overdose.

Answer 13

Supportive

-it is not reversible, must wait for the drug to be metabolized and excreted

Question 14

In what 3 groups is succinylcholine use contraindicated?

Answer 14

1. Pts. with unhealed skeletal muscle injury
2. Pts. with 3rd degree burns (risk of dysrhythmia or cardiac arrest)
3. pediatric pts. (risk of hyperkalemia)

Question 15

What are 3 major differences between depolarizing NM blockers and non-depolarizing NM blockers?

Answer 15

1. ND NM blockers are reversed by AChase agents
   D NM blockers are enhanced by AChase agents
2. D NM blockers produced fasciculations and post-op pain
3. ND NM blockers increase tetanic fade