Anti-Cholinergics

Question 1

What is the Mechanism of action of Atropine?

Answer 1

blocks muscarinic ACh receptors

Question 2

what are the main clinical uses of atropine? (there are a lot ~ 5)

Answer 2

1) EYES: Used to dilate pupils (mydriasis), to paralyze accommodation reflex (cycloplegia)
2) GI: antispasmodic
3) Urinary Retention
4) HEART: Bradycardia, 2nd degree heart block (mobitz I)
5) organophosphate poisoning

Question 3

Can atropine cross BBB?

Answer 3

yes

Question 4

MOA of Antimuscarinics in the Cardiovascular system

Answer 4

May block pre-synaptic sites first and increase release of Ach and lower HR. then is works at POST-SYNAPTIC M2 sites on SA node and increases HR

Question 5

MOA of anti-muscarinics on secretions?

Answer 5

work at M3 receptors- blocks salivary glands.

produces dry mouth, dry eye (blocks lacrimal and sweat glands)

Question 6

MOA of anti-muscarinics on eyes? 2 main effects.

Answer 6

M3- topical:

1) Mydriatic (blocks pupillae sphincter muscle)
2) cycloplegic effects (blocks ciliary muscle, loss of accommodation)

Question 7

If you wanted to block secretions for surgery, which receptor would you want the anti-muscarinic to work at?

Answer 7

M3

Question 8

In which cases can anti-muscarinics (like atropine) be used as antidote?

Answer 8

cholinergic agonists, esterase inhibitors and some mushroom poisonings

Question 9

What is the therapeutic use for Homatropine?

Answer 9

EYE: cycloplegic (to temporarily paralyze accommodation), and as a mydriatic (to dilate the pupil)
GI: reduce motility of GI tract (given with histamine H2 receptor antagonist to treat peptic ulcers)

Question 10

What are the 6 antimuscarinics that are tertiary amines?

Answer 10

1) atropine
2) scopolamine
3) homatropine
4) tropicamide
5) benztropine
6) darifenacin

Question 11

what are the 2 antimuscarincs that are quaternary ammonium compounds?

Answer 11

1) glycopyrrolate

2) ipratropium

Question 12

what are the 4 ganglionic blocking drugs?

Answer 12

1) nicotine
2) meccamylamine
3) glycopyrrolate
4) ipratopium

Question 13

What is the therapeutic use of tropicamide?

Answer 13

used in eye exams: cycloplegic (to temporarily paralyze accommodation), and as a mydriatic (to dilate the pupil). short acting when applied as eye drops. It is used to allow better examination of the lens, vitreous humor, and retina.

may also be used before or after eye surgery.

Question 14

Adverse effects of antimuscarinics

Answer 14

dry mouth
blurred vision
tachycardia
constipation
inhibition of sweating

larger doses:
restlessness, confusion, hallucinations, delerium

children more susceptible to delirum and hallucination (CNS side affects)
patch not approved in children

Question 15

what drug should you give to reverse serious overdose of antimuscarinics?

Answer 15

Physostigmine

Question 16

What are the therapeutic uses of Scopolamine?

Answer 16

similar to atropine– acts more in CNS and has longer duration of action.

Anti-nausea for motion sickness.
Block memory for surgery

Question 17

higher doses of scopolamine produce what?

Answer 17

excitement

Question 18

side effect of scopolamine?

Answer 18

blockage of memory formation

Question 19

What are the therapeutic uses of ipratropium?

Answer 19

inhalation– used to treat asthma or COPD

nasal spray– rhinitis

Question 20

What are the therapeutic uses of Benztropine?

Answer 20

used to reduce the side effects of antipsychotic treatment. No longer recommended to reverse tumors in Parkinsons because it alters balance.

Question 21

What drug can reverse the effects of Donepezil (CNS cholinesterase inhibitor for Alzheim’ers)?

Answer 21

Benztropine

Question 22

What are the 5 NT receptors sites important in the vomiting reflex?

Answer 22

M1
D2
H1
5-HT3- serotonin
NK1- Substance P

Question 23

What tract in the brain do anti-emetics work on?

Answer 23

nucleus tractus solitarius

Question 24

What is the specific MOA of Darifenacin?

Answer 24

competitive muscarinic blocker selective at M3 sites

Question 25

What are the therapeutic uses of Darifenacin?

Answer 25

used for overactive bladders

Question 26

what is another drug that can be used to help an overactive bladder aside from darifenacin?

Answer 26

Mirabegon (Beta-3 agonist)

Question 27

Cholinergics do what to the detrusor muscle of bladder?

Answer 27

contraction-- void urine

Question 28

adrenergics (beta-3) do what to the detrusor muscle of bladder?

Answer 28

relaxed- urine storage

Question 29

What are the therapeutic uses of Glycopyrrolate?

Answer 29

1) blocks vagal reflees during intubation 2) blocks drooling in cerebral palsy 3) blocks secretions in stomach to help with peptic ulcers doesnt cross BBB

Question 30

ganglionic blockers act where?

Answer 30

work on nicotinic receptors on ganglia no selectivity to SNS or PNS and are not physiologically effective as neuromuscular junction antagonists.

Question 31

Nicotine

Answer 31

- when inhaled is absorbed 90% by lungs Has higher affinity for CNS receptors and at high concentrations will work on ganglia. Ganglionic blockade occurs later (? don't think I really get whats going on here-- sorry)

Question 32

Ganglionic blockers peripheral muscarinic effects on sweat glands

Answer 32

diaphoresis

Question 33

Ganglionic blockers peripheral muscarinic effects on heart, exocrine glands and smooth muscle

Answer 33

``` bradycardia ventricular dysrythrmias torsades des poins AV blocks Cardiac arrest miosis blurred vision lacrimation etc. ```

Question 34

mecamylamine MOA

Answer 34

competitive ganglionic blocker prevents stimulation of postynaptic receptors by ACh released from presynaptic nerve endings.

Question 35

clinical use of mecamylamine?

Answer 35

used for severe hypertension and uncomplicated cases of malignant HTN. Long duration

Question 36

what is the route of administration of mecamylamine and can it cross BBB?

Answer 36

orally active and can cross BBB and cause CNS sedation, tremor, abnormal movements and mental changes

Question 37

Big picture effects of ganglion blockers on 1) CNS 2) EYE 3) CV 4) GI 5) GU

Answer 37

1) CNS --> sedation, tremor, abnormal mvmt 2) LOss of accomodation, some dilation or mydriasis 3) CV: drop in BP, moderate tachy 4) GI: GI motility reduced, marked constipation 5) GU: urinary retention, impaired sexual function

Question 38

Major (BIG PIC) therapeutic uses for anticholinergics: 1) CNS (3) 2) EYE (3) 3) GI (2) 4) GU (1) 5) Secretions (2) 6) Respiratory (1) 7) CV (1)

Answer 38

1) CNS: atropine vs. poisons (muscarinic agonist poisonis, cholinesterase inhibitors) benztropine (used in parkinsons to prevent tremors) scopolamine (motion sickness prevention) 2) homatropin, atropine and tropicamide for eye exams (mydriasis and cycloplegia) 3) atropine, glycopyrrolate (diarrhea) 4) Darifenacin (M3, urge incontinence) 5) atropine, glycopyrrolate (decreased salivation, bronchial secretions for surgery, rhinorrhea, sweating, acids in stomach) 6) ipratropium (bronchial asthma and copd) 7) Atropine (CPR, bradycarida, second degree heart block)