Direct Acting Muscarinic Receptor Agonists

Question 1

Hydrolyzed rapidly

Binds both nicotinic and muscarinic receptor

Answer 1

Acetylcholine

Quaternary Nitrogen Analogs

Question 2

Primarily muscarinic activity

Hydrolyzed more slowly by acetylcholinesterase (AchE)

Answer 2

Methacholine

Question 3

Rx: diagnosis of Asthma
Toxicity: bronchiole constriction
Contraindication: b-blockade

Answer 3

Methacholine

Question 4

Muscarinic and nicotinic activity

Resistant to hydrolysis by AchE

Answer 4

Carbachol

Question 5

Rx: topical miotic agent for ocular surgery
and glaucoma
Toxicity: excessive muscarinic activation
i.e., bronchoconstriction, reduced cardiac
conduction

Answer 5

Carbachol

Question 6

Muscarinic selectivity
Resistant to hydrolysis by cholinesterases
Less CV effects (less M2 affinity

Answer 6

Bethanechol

Question 7

Rx: post-op urinary retention
neurogenic bladder atony
Toxicity: bradycardia, bronchoconstriction
Contraindications: asthma, peptic ulcer, bradycardia

Answer 7

Bethanechol