Muscarinic Antagonist

Question 1

Which of the following has better CNS penetration? (Atropine or Scopolamine)

Answer 1

Scopolamine

Question 2

Atropine

Answer 2

Highly selective for Muscarinic receptors but non-selective among its subtypes.
-At low doses causes slight cardiac slowing and high doses acceleration of heart
Decrease secretions (dry mouth and eyes), cause bronchodilation, relax bladder and GI.

Question 3

What are the 3 treatments of Atropine?

Answer 3

-Acute Myocardial infarction cause by excessive vagal tone.
-Block responses of vagal reflexes induced by surgical manipulation.
-Anticholinergic Poisoning

Question 4

Why is atropine and scopolamine not used ophthalmic examination?

Answer 4

They have a long duration of effects (days) compared to tropicamide (min), cyclopentolate (hr), and Homatropine (hr).

Question 5

Which should be the bronchodilator of choice in patients with COPD?

Answer 5

Anticholinergics (Ipatropuim, Titropium, etc; M3 selective)
-Beta 2 agonist may be associated with worsening of disease control.

Question 6

Why is glycopyrrolate is considered for treating COPD instead or along side LABAS?

Answer 6

It is slowly absorbed from the lungs and rapidly eliminated from the bloodstream.

Question 7

True or Falrse: Anticholinergic agents can treat overactive urinary bladder and urinary incontinence and enuresis in children?

Answer 7

True

Question 8

Why is oxybutybin preferred as a transdermal patch?

Answer 8

Decrease side effect of xerostomia.

Question 9

Match the following:
Tolterodine
Fesoterodine
Tropium
Darifenacin
Solifenacin

Eliminated by Kidney
Highly selective for M3
Prodrug
metabolized by CYP2D6 and higher patient acceptance

Answer 9

Tolterodine - metabolized by CYP2D6 and higher patient acceptance
Fesoterodine - prodrug
Tropium - eliminated by kidneys
Darifenacin - Highly selective for M3
Solifenacin - Highly selective for M3

Question 10

What are the treatments for the GI tract?

Answer 10

Pirenzipine and Telenzepine (M1 selective) inhibits gastric acid secretion

Dicyclomine are weak antagonist for IBS

Question 11

What drug is used for motion sickness?

Answer 11

Scopolamine crosses the BBB, and used prophylactically

Question 12

How does tremors occurs in Parkinson’s Disease?

Answer 12

Excess of Cholinergic activity caused by deficiency of dopaminergic activity.

Question 13

Levodopa

Answer 13

Dopamine precursor drug for PD

Question 14

Treatment for PD

Answer 14

Anti Muscarinic agents: Banztropinr and Trigexyphenidyl

-Glycopyrrolate decrease drooling