Pharmacology of Neuromuscular and Ganglionic blockers

Question 1

Ganglionic blockers description

Answer 1

• nicotinic receptor antagonist
• rarely used
• block reflexes : baroreceptor, pupillary

Question 2

Trimethaphan uses

Answer 2

hypotension for surgery

Question 3

Mecamylamine uses

Answer 3

tourettes, smoking cessation, severe hypertension

Question 4

Vascular smooth muscle tone with SANS and PANS

Answer 4

SANS > PANS
endogenous tone = mild vasoconstriction
blockade = vasodilation

Question 5

All other ANS function with SANS and PANS

Answer 5

PANS > SANS
endogenous tone = mild bradycardia
blockade = tachycardia

Question 6

Neurmomuscular blockers function

Answer 6

block acetylcholine transmission

presynaptically; decrease Ach formation/release, increase metabolism

Question 7

Function on skeletal muscle

Answer 7

block nicotinic receptors on skeletal muscle

drugs have a quaternary ammonium = peripherally restrict

Question 8

Use for neuromuscular blockers

Answer 8

• surgery, orthopedic procedures, bronchoscopy, artificial respiration/intubation
• relaxes skeletal muscle

Question 9

Sequence of muscle paralysis by curare/neuromuscular blocker

Answer 9

1. muscles of eye, speech
2. fingers, toes, limbs
3. intercostals followed by diaphragm

Question 10

Similarity between neuromuscular blocker and GBS

Answer 10

peripheral nerve disorder
progression worsens between 1day-2wks
caused by certain bacterial or viral infections

Question 11

Neuromuscular blockers curare vs succinylcholine

Answer 11

• agonist nicotinic Ach receptors

- persistent depolarization makes muscle fiber resistant to further stimulation by Ach

Question 12

Succinylcholine duration and metabolism

Answer 12

depolarizing
short duration of 5-10min
metabolized to choline by butyrylcholinesterase
slower than ACHe
choline increases BP

Question 13

Succinylcholine time and use

Answer 13

fast onset, short duration

used in trauma for intubation and electroconvulsant therapy

Question 14

Contraindications for succinylcholine

Answer 14

hyperkalemia and cause of cardiac arrest

Question 15

Neuromusclar blockers curare-like vs succinylcholine

Answer 15

non-depolarizing

antagonist nicotinic ACh receptors

Question 16

Pancuronium duration

Answer 16

long duration, >180min

Question 17

Vecuronium, Atracurium duration

Answer 17

intermediate duration, 30-40min

Question 18

Trimethaphan duration

Answer 18

short acting

Question 19

Benefits of curare like neuromuscular blockers

Answer 19

easily reversible and widely used

Question 20

Types of cholinesterases

Answer 20

Acetylcholinesterase - located in synapse, prefers Ach

Plasmacholinesterase

Question 21

Description of Plasmacholinesterase

Answer 21

- butyrylcholinesterase(BuChE)
located in plasma
BuCH > Ach
succinycholine
local anesthetics(procaine)

Question 22

Carbamates description

Answer 22

acetylcholinesterase inhibitors
quarternary or tertiary amine groups
temporary covalent modification to AChE
reversible
covalent carbamate group will dissociate in 0.5-8hrs

Question 23

Physostigmine description

Answer 23

tertiary amine
enters CNS
IM, IV, local administration
used for atropine OD; blocks CNS and nonCNS

Question 24

Physostigmine treatment for

Answer 24

Glaucoma, Alzheimer’s

Question 25

Neostigmine and Pyridostygmine description

Answer 25

quartanary amine
peripherally restricted
IM, IV, local administration

Question 26

Neostigimine and Pyridostygmine treatment for

Answer 26

Myasthenia gravid
reversal of NMB
postoperative ileus, bladder distention

Question 27

Organophosphates description

Answer 27

irreversible, covalent binding ACHe inhibitors

long last, >week

Question 28

Treatment of organophosphates

Answer 28

glaucoma, but not common

Question 29

Dangerous organophosphates

Answer 29

Nerve gas: sarin, soman
Insecticides: Malathion(prodrug), Parathion, Diazinon
-rapidly inactivated in mammals