week 4- Cholinergic-Blocking Agents

Question 1

Cholinergic Blockers: Definition

Answer 1

Drugs that block or inhibit the actions of acetylcholine (ACh) in the parasympathetic nervous system (PSNS)

By blocking the PSNS it allows the SNS
to dominate, producing similar effects as the
adrenergic
mimics fight-flight response

Effects are opposite to cholinergic

Question 2

Cholinergic Blockers: Mechanism of Action

Answer 2

Competitive antagonists

Competes with Ach

Block ACh at the muscarinic receptors in the PSNS

Question 3

Chemical Class

Answer 3

Natural:
Belladonna
Atropine
Scopolamine

Synthetic:
Benztropine(Cogentin)
Tolterodine(Detrol)
Ipratropium(Atrovent)
Tiotropium(Spiriva)

Question 4

Diphenhydramine -

Answer 4

an antihistamine possessing anticholinergic, antitussive, antiemetic and sedative properties

Question 5

Dimenhydrinate is a salt of two drugs:

Answer 5

diphenhydramine, and a derivative of theophylline

Question 6

Mechanism of Action

Answer 6

Once these drugs bind to receptors, they inhibit nerve transmission at these receptors

The effects are opposite to cholinergic drugs

Question 7

Cholinergic Blockers: Drug Effects

Answer 7

Cardiovascular
i. Small doses: decrease heart rate
ii. Large doses: increase heart rate
CNS
i. Small doses: decrease muscle rigidity and tremors
ii. Large doses: drowsiness, disorientation, hallucinations
——. ie. Gravol/ dimenhydrinate, Amantadine (also used in Parkinson’s)

Eye ie. atropine
 Dilated pupils (mydriasis)
 Decreased accommodation due to paralysis
of ciliary muscles (cycloplegia)

Gastrointestinal  
	ie  butylscopolamine(buscopan)
	Relax smooth muscle tone of GI tract
	Decrease intestinal and gastric secretions
	Decrease motility and peristalsis 

Genitourinary
 ie. tolterodine (detrol), oxybutynin (ditropan)
 Relaxed urinary muscle wall
 Increased constriction of internal sphincter
 Result: urinary retention (for bladder incontinence)
 Glandular ie. atropine
 Decreased bronchial secretions, salivation, sweating (dries up secretions)

Question 8

Cholinergic Blockers Indications: CNS

Answer 8

Decreased muscle rigidity, muscle tremors and muscle spasms

Treatment of Parkinson’s disease (ie. Amantadine)

Treatment of drug-induced EPS (extrapyramidal reactions), ie. benztropine (Cogentin)

Question 9

Parkinson’s decrease level of acetylcholine (blocks)

Answer 9

.

Question 10

Cholinergic Blockers Indications: Respiratory

Answer 10

 Asthma/ COPD/Exercise-induced bronchospasms
 Blocking the cholinergic stimulation of the PSNS allows unopposed action of the SNS
Results:
 Decreased secretions from nose, mouth, pharynx, bronchi
 Relaxed smooth muscles in bronchi and bronchioles
 Decreased airway resistance
 ie. ipratropium bromide(Atrovent)
 ie. tiotropium (Spiriva)

Question 11

Cholinergic Blockers Indications: Gastrointestinal

Answer 11

	Peptic ulcer disease
	Irritable bowel syndrome (anti-spasmotic)
	GI hypersecretory states
	Motion sickness (blocks vomiting center in the brain)
	Blockade of PSNS results in:
        Decreased secretions
	Relaxation of smooth muscle
	Decreased GI motility and peristalsis
	ie. scopolamine, hyoscine (Buscopan)

Question 12

Cholinergic Blockers Indications: Genitourinary

Answer 12

Relief of urinary incontinence

ie. tolterodine (detrol), ditropan (oxybutynin)

Question 13

Side/Adverse Effects

Answer 13

Increased heart rate, dysrhythmias
CNS excitation, restlessness, irritability, disorientation, hallucinations, delirium
Dilated pupils, decreased visual accommodation, increased intraocular pressure
Decreased salivation, decreased gastric secretions, decreased motility

Urinary retention

decrease in sweating

Question 14

Physostigmine

Answer 14

An anticholinesterase which is a specific antidote for anticholinergic poisoning
It crosses in the CNS and reverses both central and peripheral anticholinergic effects

Used for drug overdoses
Symptoms of pesticide use

Question 15

Overdosing can cause life-threatening problems

Answer 15

.

Question 16

Blurred vision may cause problems with driving or operating machinery
.

Answer 16

.

Question 17

Dry mouth may occur.

Answer 17

.

Question 18

Anticholinergics taken by the geriatric patient may lead to

Answer 18

higher risk for heatstroke due to the effects on heat-regulating mechanisms

Question 19

Teach patients to limit physical exertion, and avoid

Answer 19

high temperatures and strenuous exercise

Question 20

3. Anticholinergic drugs inhibit the action of

Answer 20

ACh

Question 21

4. Anticholinergic drugs are used in Parkinson’s disease because they decrease

Answer 21

_TREMERS___, __DROOLING___, __TWITCHING__, and _____________________.

Question 22

5. Drug of choice for Parkinson’s is

Answer 22

_AMANTADINE__.

Question 23

6. ATROPINE

Answer 23

is also used in the treatment ofBRADYCARDIA and is found on the crash cart. FOR HYPOTENSION= EPINERPHRINE

Question 24

8. Which class of drugs affects the heat regulating center

Answer 24

__ANTI-CHOLINERGIC___.

Question 25

9. Urinary retention is a symptom of which class

Answer 25

____ANITCHOLERGNIC.

Question 26

receptors are located in the ganglia of the PSNS and SNS.

Answer 26

__NICATINIC __

Question 27

The enzyme responsible for breaking down Ach

Answer 27

___CHOLINASTRIS

Question 28

14. Parkinson’s is due to a decrease of _.

Answer 28

___DOPAMINE______

Question 29

15. Glaucoma and BPH patients should avoid _

Answer 29

_ANTI-CHOLINERGIC__ class.

Question 30

another adverse effect of

Answer 30

sensitivity to light