Cholinergic Agonists and Antagonists

Question 1

drugs that stimulate the PNS are called ___

Answer 1

cholinergic agonists or parasympathomimetics (mimic the neurotransmitter acetylcholine)

Question 2

____ is the neurotransmitter located at the ganglions and the parasympathetic terminal nerve endings

Answer 2

acetylcholine (ACh)

Question 3

the two types of cholinergic receptors

Answer 3

muscarinic (stimulate smooth muscles and slow HR)

nicotinic (neuromuscular which affect the skeletal muscles)

Question 4

two types of cholinergic agonists

Answer 4

direct-acting (act on receptors)

indirect-acting (inhibit action of enzyme acetylcholinesterase (AChE))

Question 5

AChE does what

Answer 5

destroys acetylcholine

Question 6

major responses of cholinergic agonists

Answer 6

stimulate bladder and GI tone, miosis (constrict pupil), and increase neuromuscular transmission

decreased HR and BP, increased salivary, GI, and bronchial secretions

Question 7

are primarily selective to the muscarinic receptors but are nonspecific because the muscarinic receptors are located in the smooth muscle of the GI and genitourinary tracts, glands, and heart

Answer 7

direct-acting cholinergic agonists

monitor LFTs

Question 8

a direct-acting cholinergic agonist that is used to increase urination in the treatment of urinary retention and neurogenic bladder

Answer 8

bethanechol chloride

Question 9

a direct-acting cholinergic agonist that is used to treat gastroparesis, nausea, and GERD

Answer 9

metoclopramide

Question 10

what is the direct-acting cholinergic agonist given in glaucoma that causes miosis

Answer 10

pilocarpine

Question 11

what is the antidote to cholinergics?

Answer 11

IV atropine (anticholinergic)

Question 12

do not act on the receptors, instead, they inhibit or inactivate the enzyme cholinesterase, permitting acetylcholine to accumulate at the receptor site

Answer 12

indirect-acting cholinergic agonists

Question 13

a ChE inhibitor drug binds with ChE allowing acetylcholine to activate the muscarinic and nicotinic cholinergic receptors. This action permits skeletal muscle stimulation, which increases the force of muscular contraction. Because of this action, ChE inhibitors are useful to increase muscle tone for patients with ______

Answer 13

myasthenia gravis

Question 14

___ are used to produce pupillary constriction in the treatment of glaucoma and to increase muscle strength in patients with myasthenia gravis

Answer 14

reversible ChE inhibitors

-stigmine

Question 15

drugs that inhibits the actions of acetylcholine by occupying the acetylcholine receptors

Answer 15

cholinergic antagonists (anticholinergics)

Question 16

major body tissues and organs that are affected by anticholinergic drugs

Answer 16

heart, respiratory tract, GI tract, urinary bladder, eyes, and exocrine glands

Question 17

what are the major responses to anticholinergics

Answer 17

decrease in GI motility, decrease in salivation, mydriasis (pupil dilation), increase HR

other effects: decreased bladder contraction, which can result in urinary retention, and decreased rigidity and tremors related to neuromuscular excitement

Question 18

what are the therapeutic uses of atropine (anticholinergic)

Answer 18

preop med to reduce salivation, increase HR for bradycardia, neuromuscular blockade reversal, cholinergic crisis, and mydriasis and cycloplegia for ocular exams

Question 19

side effects of atropine (or like drugs)

Answer 19

xerostomia (dry mouth), nasal dryness, blurred vision, tachycardia, constipation, and urinary retention

nausea, HA, dehydration, seizures, hypotension or HTN, photophobia, and coma

**can’t pee, can’t see, can’t shit, can’t spit

Question 20

anticholinergics affect the CNS by suppressing the tremors and muscular rigidity of parkinsonism, but they have little effect on mobility and muscle weakness

Answer 20

trihexyphenidyl, hydrochloride, biperiden, and benztropine

use caution because of sedative effect