B.4 Muscarinic receptor blocking drugs

Question 1

other names for cholinoceptor blockers

Answer 1

cholinergic antagonists
muscarinic antagonists
parasympatholytics

Question 2

list the muscarinic antagonists

Answer 2

tropins: 
Atropine
scopolamine 
Butyl-scopolamine 
Benztropine
Ipratropium
Tiotropium
non-tropins: 
Cyclopentolate
procyclidine 
solifenacin 
oxybutynin
Tolterodine

Question 3

list non-selective Muscarinic antagonists

Answer 3

Atropine
cyclopentolate
scopolamine 
Butyl-scopolamine 
procyclidine
Benztropine

Question 4

Adverse effects of muscarinic antagonists

Answer 4

opposite of "DUMBBELSS":
↓ secretions (salivary, sweat)
Mydriasis, cycloplegia--> blurred vision
glaucoma exacerbation
hyperthermia ( with vasodilation)--> redness
tachycardia
CNS effect (sedation, hallucination)
Urinary retention
Constipation
bronchodilation
inhibit gastric secretion

Question 5

duration of action of Atropine

Answer 5

2-4 hours

*mydriasis effect may persist for 8 days

Question 6

list muscarinic antagonists that enter the CNS (lipid soluble)

Answer 6

atropine
scopolamine
procyclidine 
benztropine 
Trihexyphenidyl

Question 7

indications for atropine

Answer 7

1. mydriatic and cycloplegic agent- Opthalmology
2. antispasmodic, antisecretory, antidiarrheal
3. Reverse AV block (1st degree)
4. Bradyarrhythmia (IV administration)
5. Antidote for AchE inhibitor toxicity -Neostigmine, OPS

Question 8

when should we avoid giving atropin and why?

Answer 8

in kids- sympatholytic effect, inhibits sweating –> skin is dry–> no heat evaporation mechanism–> Temperature ↑

Question 9

how is cyclopentolate given?

Answer 9

eye drops (short-acting)

Question 10

indications for cyclopentolate

Answer 10

mydriatic and cycloplegic agent- opthalmology

inner eye inflammation (avoid fibrin formation on the iris)

Question 11

what is scopolamine for?

Answer 11

motion sickness (transdermal patch)
in high doses--> sedation

Question 12

does Butyl-scopolamine have CNS effects?

Answer 12

no

Question 13

what is Butyl-scopolamine for?

Answer 13

abdominal cramps, menstrual cramps

Question 14

how are ipratropium and tiotropium given?

Answer 14

inhaled

Question 15

what are ipratropium and tiotropium used for?

Answer 15

bronchodilators for asthma/ COPD

Question 16

indications for procyclidine, benztropine, trihexyphenidyl

Answer 16

Parkinson disease (in combination with a dopamine antagonist)
Extrapyramidal disorders (drug-induced)

Question 17

indications for solifenacin, oxybutynin and Tolterodine

Answer 17

Bladder spasm (postoperative, neurogenic) 
Urinary incontinence

Question 18

why is it better to give Tropicomide and not atropin for an eye examination?

Answer 18

only lasts a few hours

Question 19

systemic indication for glycopyrrolate?

Answer 19

extensive salivation

Question 20

what is Pralidoxime (2-PAM) and how is it given?

Answer 20

Cholinesterase regenerator
Antagonist of organophosphate (IV)
displaces the phosphate from the serine residue

Question 21

when is Pralidoxime used?

Answer 21

as an antidote for OPS poisoning

give early as possible

Question 22

why is it important to give Pralidoxime as early as possible?

Answer 22

when the OPS- AchE complex reaches “aging”, Pralidoxime can no longer reverse the effect