Anticholinesterase Agents

Question 1

Competitive (reversible) inhibition of AChE

Answer 1

1. block ACh degradation, enhances effects of ACh
2. at high doses, AChE can produce effects at all sites where ACh is NT (muscarinic, ganglionic, NMJ, CNS)
3. at therapeutic doses, effects limited to muscarinic receptors at NMJ

Question 2

Prototype anticholinesterase

Answer 2

Neostigmine

Question 3

Neostigmine - Pharmacological Effects

Answer 3

muscarinic response
neuromuscular response
    low dose - increase contraction
    high dose - reduce contraction
**only inhibitor that is also an agonist at NMJ nicotinic receptors**

Question 4

What is the only AChE agent that is also an agonist at NMJ nicotinic receptors?

Answer 4

neostigmine

Question 5

Neostigmine - therapeutic uses

Answer 5

Myasthenia gravis
reversal of competitive neuromuscular blockade
postop bladder distension/urinary retention

Question 6

Neostigmine - Side Effects

Answer 6

excessive muscarinic stimulation (treat with atropine)

neuromuscular blockade, respiratory depression @ toxic dose

Question 7

Neostigmine - Contraindications

Answer 7

asthma, peptic ulcers, _____

Question 8

Physostigmine - drug classification

Answer 8

AChE inhibitor

Question 9

Physostigmine - actions

Answer 9

crosses BBB

no direct agonist activity

Question 10

Physostigmine - Uses

Answer 10

Treats atropine poisoning and other drugs that cause central/peripheral muscarinic blockade

Question 11

Donepezil - drug classification

Answer 11

AChE inhibitor

Question 12

Donepezil - therapeutic use

Answer 12

cognitive decline in Alzheimer pts

- improves cognition, not disease-modifying

Question 13

Organophosphorus Compounds are __________ inhibitors

Answer 13

irreversible

Question 14

OP compound prototype

Answer 14

malathion

Question 15

Malathion - characteristics

Answer 15

high lipid solubility

absorbed via all routes, skin included

Question 16

What is the common source of accidental/agricultural poisoning?

Answer 16

Malathion, irreversible inhibitors

Question 17

Malathion - therapeutic use

Answer 17

head lice

Question 18

What is echothiophate occasionally used to treat?

Answer 18

open-angle glaucoma

Question 19

OP Poisoning Diagnosis (Cholinergic crisis)

Answer 19

M: sweating, salivation, miosis, urination, defecation
N: muscle weakness, fasciculation, paralysis
CNS: confusion, ataxia, convulsions, coma, respiratory depression

Question 20

What clinical test can be used to detect OP poisoning?

Answer 20

Depressed plasma cholinesterase activity

Question 21

OP Poisoning - Treatment

Answer 21

Atropine: large doses, short intervals, blocks M
Pralidoxime: reactivates AChE only at NMJ (MUST admin before “aging”)