Chapter 21 Cholinergic-Blocking Drugs

Question 1

Cholinergic Blocking Drugs

Answer 1

Drugs that block the action of acetylcholine and substances similar to acetylcholine at receptor sites in the synapse

Question 2

Mydriasis

Answer 2

dilation of the pupil of the eye, caused by contraction of the dilator muscle of the iris

Question 3

Parasympatholytics

Answer 3

Drugs that reduce the activity of the parasympathetic nervous system; also called anticholinergics

Question 4

True or False: the parasympathetic nervous system is the same as the sympathetic nervous system?

Answer 4

False, The parasympathetic nervous system is the branch of the autonomic nervous system with nerve functions opposite those of the sympathetic nervous system

Question 5

What does a cholinergic receptor do?

Answer 5

A cholinergic receptor is one that binds acetylcholine and mediates its actions.

Question 6

What are the different names for anticholinergics?

Answer 6

Cholinergic blockers, anticholinergics, parasympatholytics, and antimuscarinic drugs

Question 7

What do parasympatholytics do?

Answer 7

They are a class of drugs that block or inhibit the actions of acetylcholine in the parasympathetic nervous system.

Question 8

What do Cholinergic blocking drugs do?

Answer 8

Cholinergic blocking drugs block the action of the neurotransmitter acetylcholine at the muscarinic receptors in the PNS. Acetylcholine that is released from a stimulated nerve fiber is then unable to bind to the receptor site and fails to produce a cholinergic effect.

Question 9

What does anticholinergics allow for?

Answer 9

Anticholinergics have many of the same effects as the adrenergics. Blocking the parasympathetic nerves allows the sympathetic (adrenergic) nervous system to dominate.

Question 10

True or False: cholinergic blockers are competitive antagonists?

Answer 10

True, they compete with acetylcholine for binding at the muscarinic receptors of the PNS. Once they have bound to the receptor, they inhibit cholinergic nerve transmission. This occurs at the neuroeffector junction, or the point where the nerve ending reaches the effector organ such as smooth muscle, cardiac muscle, and glands.

Question 11

True or False: Cholinergic blockers have partial effects at low dosages?

Answer 11

False, cholinergic blockers have little effect at the nicotinic receptors, although at high doses they have partial blocking effects.

Question 12

What are the major sites of action of the anticholinergics ?

Answer 12

The heart, respiratory tract, gastrointestinal tract, urinary bladder, eye, and exocrine glands.

Question 13

True or False: Anticholinergic effects decrease heart rate

Answer 13

False, Anticholinergic effects on the cardiovascular system are seen as an increase in heart rate.

Question 14

True of False: cholinergic blockers cause mydriasis?

Answer 14

Cholinergic blockers keep the sphincter muscle of the iris from contracting, which results in dilation of the pupil (mydriasis) and paralysis of the ocular lens (cycloplegia).

Question 15

True of False: Anticholinergics are indicated for Parkinson’s?

Answer 15

True

Question 16

What are the cholinergic blocking effects of the Cardiovascular system?

Answer 16

Small doses= decrease heart rate

Large doses= increase heart rate

Question 17

What are the cholinergic blocking effects of the central nervous system?

Answer 17

Small doses: decrease muscle rigidity and tremors. Large doses: causes drowsiness, disorientation, hallucinations.

Question 18

What are the cholinergic blocking effects of the eye?

Answer 18

Dilate pupils (mydriasis), decrease accommodation by paralyzing ciliary muscles (cycloplegia)

Question 19

What are the cholinergic blocking effects of the gastrointestinal body system?

Answer 19

Relaxed smooth muscle tone of gastrointestinal tract, decrease intestinal and gastric secretions, decrease motility and peristalsis.

Question 20

What are the cholinergic blocking effects of genitourinary body system?

Answer 20

Relax detrusor muscle of bladder, increase constriction of internal sphincter, these two effects may result in urinary retention.

Question 21

What are the cholinergic blocking effects of glandular body system?

Answer 21

decrease bronchial secretions, salivation, and sweating.

Question 22

What are the cholinergic blocking effects of the respiratory system?

Answer 22

Decrease bronchial secretions, dilate bronchial airways.

Question 23

What are some contraindications to the use of anticholinergic drugs?

Answer 23

Drug allergy
angle closure glaucoma
acute asthma
respiratory distress
myasthenia graves
acute cardiovascular instability 
GI or GU tract obstruction

Question 24

What are Cholinergic blockers adverse effects for the cardiovascular body system?

Answer 24

Increased heart rate
dysrhymias
tachycardia,
palpitations

Question 25

What are Cholinergic blockers adverse effects for the eye?

Answer 25

``` dilated pupils (causing blurred vision) increased intraocular pressure ```

Question 26

What are Cholinergic blockers adverse effects for the central nervous system?

Answer 26

``` Excitation, restlessness, irritability, disorientation, hallucinations, delirium, ataxia, drowsiness, sedation, confusion ```

Question 27

What are Cholinergic blockers adverse effects for the gastrointestinal system?

Answer 27

decreased salivation gastric secretions motility (causing constipation)

Question 28

What are Cholinergic blockers adverse effects for the genitourinary system?

Answer 28

Urinary retention

Question 29

What are Cholinergic blockers adverse effects for the glandular system?

Answer 29

Decreased sweating

Question 30

What are Cholinergic blockers adverse effects for the respiratory system?

Answer 30

Decreased bronchial secretions

Question 31

What is the treatment for cholinergic blocker overdose?

Answer 31

symptomatic and supportive therapy. The patient should be hospitalized with continuous electrocardiographic monitoring. Activated charcoal is effective in removing from the GI tract and any drug that has yet to been absorbed.

Question 32

What are drug interactions most commonly reported with additive anticholinergic effects?

Answer 32

Amantadine, antihistamines, antidepressants, and digoxin

Question 33

True or False: Atropine is naturally occurring antimuscarinic?

Answer 33

True

Question 34

What is atropine contraindicated in?

Answer 34

Atropine is contraindicated in patients with angle-closure glaucoma, and it should be used with caution in patients with advanced hepatic and renal dysfunction, hiatal hernia associated with reflux esophagitis, intestinal atony, obstructive GI or GU conditions, and severe ulcerative colitis.

Question 35

What is Atropine used for?

Answer 35

Treat increased heart rate, bradycardia, and ventricular asystole, and cardiopulmonary resuscitation. it is more potent than scopolamine in its cholinergic-blocking effects on the heart and in its effects on the smooth muscles of the bronchi and intestines antidote for anti-cholinesterase inhibitor toxicity or poisoning.

Question 36

What is Dicyclomine (Bentyle) used for?

Answer 36

Dicyclomine is a synthetic antispasmodic cholinergic blocker used primarily in the treatment of functional disturbances of GI motility such as irritable bowl syndrome.

Question 37

What is the contraindicated for dicyclomine?

Answer 37

``` hypersensitivity to anticholinergics angle-closure glaucome GI tract obstruction myasthenia graves paralytic ileus GI atony, toxic megacolon ```

Question 38

What is Glycopyrrolate used for?

Answer 38

Glycopyrrolate (robinul) is used as a synthetic antimuscarinic drug that blocks receptor sites in the autonomic nervous system that control the production of secretions. it is used preoperatively to reduce salivation and excessive secretions I the respiratory and GI tracts.

Question 39

What is Glycopyrrolate contraindicated with?

Answer 39

``` patients who are hypersensitive to it angle-closure glaucoma, myasthenia graves, GI or GU tract obstruction, tachycardia, myocardial ischemia, hepatic disease, ulcerative colitis, toxic megacolon ```

Question 40

What is Oxybutynin (Ditropan) used for?

Answer 40

Oxybutynin is a synthetic antimuscarinic drug used for the treatment of overactive bladder (OAB). It is also used as an antispasmodic for neurogenic bladder assoaciated with spinal cord injuries and congenital conditions such as spina bifida.

Question 41

What are the contraindications for oxybutynin?

Answer 41

Drug allergy urinary or gastric retention uncontrolled angle closure glaucoma

Question 42

What is scopolamine used for?

Answer 42

prevention of motion sickness.

Question 43

What is tolterodine used for?

Answer 43

Tolterodine is a muscarinic receptor blocker used for the treatment of urinary frequency, urgency, and urge incontience caused by bladder (detrusor) overactivity.

Question 44

Tolterodine should be avoided with patients who have?

Answer 44

angle-closure glaucome, | urinary retention