Cholinergic Receptor Inhibiting Drugs

Question 1

Do drugs the block muscarinic receptors have any effect on nicotinic receptors?

Answer 1

no

Question 2

Name the 6 tertiary amines that block muscarinic receptors.

Answer 2

atropine, scopolamine, dicyclomine, tropicamide, tolterodine, benztropine

Question 3

What effect is atropine and tropicamide used to produce and which receptor does it block?

Answer 3

mydriasis and cycloplegia (paralysis of the ciliary muscle); M3

Question 4

What is scopolamine used to treat and which receptor does it block?

Answer 4

prevent or reduce motion sickness; muscarinic, subtype unknown

Question 5

What is dicyclomine used to treat and which receptor does it block?

Answer 5

reduce transient hypermotility of the GI tract; M1 and M3

Question 6

What is tolterodine used to treat and which receptor does it block?

Answer 6

Transient cystitis, postoperative bladder spasms, incontinence; M3

Question 7

What is benztropine used to treat?

Answer 7

manifestations of parkinson’s disease

Question 8

Which if the tertiary amines crosses the blood brain barrier?

Answer 8

benztropine

Question 9

Name the 2 quaternary amines that block muscarinic receptors and which receptor do they block?

Answer 9

Ipratropium and Tiotropium; M3

Question 10

What are the 2 quaternary amines (Ipratropium and Tiotropium) used to treat and which one is longer acting?

Answer 10

asthma and COPD; Tiotropium is longer acting

Question 11

Which of the following is a ganglionic blocker and which receptor does it block?
Hexamethonium, succinylcholine, Tubocurarine, Mivacurium or Botulinum Toxin A

Answer 11

Hexamethonium; blocks Nn receptor

Question 12

Which of the following is a depolarizing blocker and which receptor does it block?
Hexamethonium, succinylcholine, Tubocurarine, Mivacurium or Botulinum Toxin A

Answer 12

Succinylcholine; blocks Nm receptor by overstimulating the receptor with depolarization causing desensitization to further Ach stimulation

Question 13

Which of the following are nondepolarizing blockers and which receptor do they block?
Hexamethonium, succinylcholine, Tubocurarine, Mivacurium or Botulinum Toxin A

Answer 13

Tubocurarine and Mivacurium; block Nm receptor

Question 14

Which of the following is a local paralytic and which does it block?
Hexamethonium, succinylcholine, Tubocurarine, Mivacurium or Botulinum Toxin A

Answer 14

Botulinum toxin A; blocks vesicle fusion and Ach release by degrading SNAP-25

Question 15

What is Hexamethonium used to treat?

Answer 15

for hypertensive emergencies and to produce hypotension for “bloodless field” surgeries; rarely used

Question 16

What is succinylcholine used for?

Answer 16

Brief procedures (ex: tracheal intubation, reset dislocated joints); short lasting effects

Question 17

What is Tubocurarine used for and how long does it last?

Answer 17

Muscle relaxant for surgery without deep anesthesia; lasts 30-60mins

Question 18

What is Mivacurium used for?

Answer 18

Muscle relaxant for surgery without deep anesthesia; hydrolyzed more rapidly than tubocurarine so its short acting

Question 19

What are the combined toxicities for the nondepolarizing and depolarizing blockers?

Answer 19

respiratory paralysis which can lead to death

Question 20

What is the non-depolarizing blocker used in capital punishment?

Answer 20

pancuronium

Question 21

Which drugs are cholinesterase inhibitors good at reversing the effects of; nondepolarizing blockers, depolarizing blockers or ganglionic blockers?

Answer 21

non-depolarizing blockers

Question 22

What is Botulinum Toxin A used for?

Answer 22

Reduce frown lines and wrinkles, achalasia (abnormal esophageal contractions) strabismus (misalignement of eyes) and oromandibular dystonia (spasms of face and jaw)

Question 23

Do ganglionic blockers block the parasympathetic nervous system, sympathetic nervous system or both?

Answer 23

both; they block the Nn receptor

Question 24

Do muscarinic receptor antagonists block the parasympathetic nervous system, sympathetic nervous system or both?

Answer 24

parasympathetic

Question 25

What is the mnemonic for an overdose of atropine (and other antimuscarinic drugs)?

Answer 25

“dry as a bone, blind as a bat, red as a beet, and mad as a hatter”

Question 26

Why is atropine a good drug to use for poisoning with cholinesterase inhibitors?

Answer 26

its a tertiary amine so it can interact well with the CNS and the peripheral muscarinic receptors

Question 27

What is meant by “dry as a bone” with overdose of antimuscarinics?

Answer 27

decreased sweating, lacrimation and salivation

Question 28

What is meant by “blind as a bat” with overdose of antimuscarinics?

Answer 28

blockade of accommodation and excessive pupil dilation

Question 29

What is meant by “red as a beet” with overdose of antimuscarinics?

Answer 29

dilation of cutaneous vessels in upper body (atropine flush)

Question 30

What is meant by “mad as a hatter” with overdose of antimuscarinics?

Answer 30

inhibition of CNS muscarinic receptors with complex consequences

Question 31

What is the atropine fever?

Answer 31

hyperthermia from the block of thermoregulatory sweating by antimuscarinics
Dangerous in infants and small kids

Question 32

How does hexamethonium lead to hypotension?

Answer 32

blood vessels main input is vasoconstrictor fibers from the SNS, so blocking the output from ganglions blocks the vasoconstriction signal leading to vasodilation and hypotension

Question 33

Which type of antimuscarinic can cross the BBB, quaternary amines or tertiary amines?

Answer 33

tertiary amines

Question 34

Is tropicamide used for long acting antagonism of M3 or short acting?

Answer 34

short acting because it is rapidly metabolized