Agonists & Antagonists

Question 1

Which is more sensitive to agonists, muscarinic or nicotine?

Answer 1

Muscarinic

Question 2

Direct acting ACh agonists

Answer 2

ACh
Carbachol
Bethanechol
Pilocarpine

Question 3

Therapeutic uses of ACh agonists

Answer 3

Glaucoma
Intraocular pressure in surgery
Treat xerostomia
Increase bladder tone and motility, also GIT motility

Question 4

Acetylcholine is used for treatment of:

Answer 4

Myasthenia gravis
Alzheimer’s disease
Reverse the action of muscle relaxants

Question 5

Ocular side effects of acetylcholine

Answer 5

Corneal swelling
Corneal clouding
Corneal decomposition

Question 6

Systemic side effects of acetylcholine

Answer 6

sweating
difficulty in breathing
hypotension
flushing
slow heart rate

Question 7

Carbachol therapeutic uses

Answer 7

• Treatment of glaucoma
• Used to constrict the pupils during cataract surgery.

Question 8

Therapeutic uses of bethanechol

Answer 8

• Increases tone and motility of bladder and GI tract
• Relaxes sphincters in bladder and GI tract, allowing them to empty

Question 9

Therapeutic uses of pilocarpine

Answer 9

• Totreat dry mouth caused by radiotherapy in people with head and neck cancerand to treat dry mouth in people with Sjögren’s syndrome
• Miotics to treat glaucoma byallowing excess fluid to drain from the eye.

Question 10

Indirect acting agonists

Answer 10

Edrophonium
Physostigmine
Neostigmine
Echothiophate

Question 11

General uses of indirect acting agonists

Answer 11

• Cause skeletal muscle contractions; hence, treatment ofmyasthenia gravis
• Used to reverse anticholinergic poisoning (antidote)

Question 12

Therapeutic uses of donezepil

Answer 12

• Used in the treatment of mild to moderate Alzheimer’s disease.
• Helps to increase memory and learning capabilities

Question 13

Side effects of indirect acting agonists

Answer 13

Bradycardia
Hypotension
Cconduction abnormalities
Headache
Dizziness
Loss of binocular accommodation

Question 14

Which drugs are known to antagonize cholinergic agents, resulting in decreased responses apart from general antagonists?

Answer 14

Antihistamines

Question 15

Depending on the type of receptor to act on, cholinergic antagonists are either classified as

Answer 15

muscarinic antagonists or nicotinic antagonists.

Question 16

Natural ACh antagonists

Answer 16

Atropine
Scopolamine

Question 17

Synthetic/semisynthetic ACh antagonists

Answer 17

anisotropine clidinium
dicyclomine glycopyrrolate
hexocyclium homatropine
ipratropium isopropamide
oxybutynin propantheline

 tolterodine   tridihexethyl

Question 18

Drug effects of cholinergic antagonists

Answer 18

Small doses:Decrease heart rate.
Large doses: Increase heart rate .
Small doses:Decrease tremors.
Large doses:Drowsiness. Hallucinations. Dilated pupils (mydriasis)

Decrease gastric secretion.
Decrease motility and peristalsis.
Increased constriction of internal sphincter causing urinary retention
Decreased bronchial secretions, salivation, sweating.

Question 19

Therapeutic Uses ofCholinergic Antagonists

Answer 19

• It is used in treatment of Parkinson’s disease by decreasing muscle rigidity and power tremors.
• Low doses: slows the heart rate.
  High doses: increases heart rate
• Used primarily for cardiovascular disorders
• Used to treat chronic bronchitis and Asthma
  Peptic ulcer disease.
• Irritable bowel disease.
• GI hypersecretory states

Question 20

Atropine is primarily used for

Answer 20

Cardiovascular disorders

Question 21

Side effects of ACh antagonists and

Answer 21

Irritability
disorientation
Haluccination
Decreased salivation
Decreased sweating
Decreased bronchial secretions