Ch.11: Anticholinesterase Drugs

Question 1

anti-cholinesterase agent

Answer 1

drugs that inhibit the enzyme AChE, which degrades Ach. Result is to intensify Ach actions via INDIRECT activation of cholinergic receptors

Question 2

are anti-cholinesterase agents agonists or antagonists?

Answer 2

NEITHER. They indirectly activate cholinergic receptors

Question 3

Butyrlcholinesterase (BuChe) fx

Answer 3

(not on list)
hydrolyzes Ach and other esters
unknown physiological role
inhibited by most AChE inhibitors

Question 4

What happens to BP after administration of AChE inhibitor?

Answer 4

drops

Question 5

classification of Anti-cholinesterase agents is based on:*

Answer 5

the duration of enzyme inhibitioin by the inhibitor, which is related to the speed with which inhibitor dissociates from the esteratic site of AChE. Chemical structure determines all of this.

Question 6

rank 3 types of anti-cholinesterase agents in order of shortest to longest acting

Answer 6

quaternary < carbamates < organophosphates

Question 7

therapeutic uses of reversible anti-AChE agents

Answer 7

• ophthalmic
• GI stimulant
• Diagnostic for myasthenia Gravis
• Anti-parasitic action

Question 8

How does edrophonium work?

Answer 8

blocks Ach breakdown at neuromuscular jx and promotes Ach stimulation of nicotiic receptors on skeletal muscle. Is a short acting agent

Question 9

contraindications for use of Anti-AChe agents

Answer 9

• ill or debilitated
• hepatic dz
• resp. dz
• pregnancy
• GI/urinary tract obstruction
• recent exp. to anti-AChE agents
• food or dairy animals
• very young or old

Question 10

Is edrophonium hydrolyzed by AChE?

Answer 10

NO

Question 11

How is edrophonium eliminated?

Answer 11

renal excretion (rapid)

Question 12

therapeutic uses of edrophonium

Answer 12

• temporary reversal of competitive muscle relaxants

- differential diagnosis of myasthenia gravis

Question 13

Therapeutic uses of neostigmine

Answer 13

-glaucoma
-treat myasthenia gravis
-ruminal or GI stimulant
-reversal agent for muscle relaxants
(anti-parasitic, pupillary constriction)

Question 14

duration of action of neostigmine

Answer 14

intermediate (1-3 hrs)

Question 15

does neostigmine cross BBB?

Answer 15

NO

Question 16

class of neostigmine

Answer 16

reversible anticholinesterase

Question 17

How is neostigmine eliminated?

Answer 17

hydrolyzed by AChE and pseudo-ChE

Question 18

class of physostigmine

Answer 18

reversible anticholinesterase

Question 19

therapeutic uses of physostigmine

Answer 19

similar to neostigmine, but exhibits greater CNS activity

Question 20

Drugs potentiated by anti-AChE agents**

Answer 20

• succinylcholine
• cocaine
• cholinomimetics
• morphine**
• acepromazine**
• adrenolytic agents

Question 21

Drugs antagonized by anti-AChE agents**

Answer 21

• atropine
• pancuronium
• glycopyrrolate
• N-butylscopolammonium

Question 22

drug that antagonizes Anti-AChE agent

Answer 22

quinine

Question 23

OP-Type acetylcholinesterase inhibitors are used in what setting?

Answer 23

agriculture for pest/rodent control, as nerve gas. Not used clinically

Question 24

parathion metabolism

Answer 24

metabolized in liver to active form (paraxon)

Question 25

How do OP agents work?

Answer 25

form covalent bond with AChE to inhibit it. Becomes irreversible

Question 26

What class is parathion?

Answer 26

irreversible anticholinesterase (OP-type inhibitor)

Question 27

most common uses of parathion***

Answer 27

agricultural insecticide, urban mosquito control, cattle dip or spray

Question 28

How can you recover from OP-type AChE inhibitors?

Answer 28

only way to recover is to make new enzyme (takes a long time!)

Question 29

Signs of acute OP poisoning

Answer 29

inhaled: ocular, respiratory
oral: GI, systemic, SLUD*
cutaneous: sweating, muscle fasciculations, systemic signs

Question 30

SLUD is assoc. with overstimulation of:

Answer 30

parasympathetic transmission in the body

Question 31

tx for OP poisoning***

Answer 31

tx SLUD symptoms with atropine. Treat with praladoxime or 2-PAM ONLY IF YOU ARE CERTAIN IT IS OP POISONING AND IT IS WITHIN THE FIRST 24 HOURS (acts as a cholinesterase inhibitor)