I - Cholinoreceptor activating and cholinesterase inhibiting drugs

Question 1

Betanechol is a direct-acting, muscarinic drug

Answer 1

MOA: Activates muscarinic (M3) receptors. Uses: Bladder and bowel atony (post-surgery or spinal cord injury.

Question 2

MNEMONICS

Answer 2

B = Betanechol = Bowel and Bladder Atony

Question 3

Pilocarpine is Cholinomimetic (direct acting, muscarinic) MOA: Activates muscarinic (M3) receptors in ciliary muscle (increasing aqueous humor outflow) and salivary glands (increasing salivation).

Answer 3

Uses: Glaucoma, Sjogren syndrome, Sicca syndrome (dry eyes and dry mouth).

Question 4

What is Sjogren syndrome?

Answer 4

an autoimmune disorder characterized by triad of a.) xerostomia (dry mouth) b.) xerosthalmia (dry eyes c.) rheumatoid arthritis.

Question 5

Nicotine is a Cholinomemitic (direct acting, nicotinic) MOA: Activates nicotinic Ach receptors (Nn and Nm)

Answer 5

Uses: Smoking Cessation. SE: ganglionic stimulation.

Question 6

Muscarinic toxicity

Answer 6

CNS stimulation, Eye: miosis, spasm of accomodation, Lungs: bronchostriction, GIT: excessive GI and genitourinary SM activity.

Question 7

Mushroom Poisoning: muscarinic and similar alkaloids responsible for short acting mushroom poisoning

Answer 7

Inocybe and Amanita muscaria.

Question 8

Nicotinic Toxicity: Ganglionic stimulation, blockade of neuromuscular end plate depolarization.

Answer 8

fasciculations and paralysis.

Question 9

Nicotinic Toxicity:

Answer 9

CNS toxicity: stimulation (convulsions) followed by CNS depression.

Question 10

MOA of Indirect-acting Cholinomimeticcs

Answer 10

bind to cholinesterase and undergo prompt hydrolysis.

Question 11

Edrophonium MOA: Inhibits Acetylcholinesterase. Amplifies endogenously released acetylcholine.

Answer 11

Uses: Myasthenia gravis (diagnosis - Tensilon test), Differentiation of cholinergic crsis and myasthenic crisis Notes: very short acting upon IV administration(TOPNOTCH)Robbins Basic Pathology, 8th ed. p.10

Question 12

Neostigmine. MOA: Inhbits acetylcholinesterase and amplifies endogenously released acetylcholine.

Answer 12

Uses: Myasthenia gravis (treatment), Reversal of nondepolarizing neuromuscular blockade, Ogilve syndrome, Glaucoma. Notes: Muscarinic effects are blocked by Atropine.(TOPNOTCH)Robbins Basic Pathology, 8th ed. p.8

Question 13

What is Myasthenia gravis?

Answer 13

autoimmune destruction of Nicotinic Ach receptors characterized by: fluctuating muscle, weakness, ocular symptom, bulbar symptom and proximal muscle weakness. (TOPNOTCH)Robbins Basic Pathology, 8th ed. p.23

Question 14

How does EDROPHONIUM differentiate myasthenic crisis from cholinergic crisis?

Answer 14

IMPROVES muscle strength in myasthenic crisis, WEAKENS muscle strength in cholinergic crisis.

Question 15

Cholinergic crisis.

Answer 15

excessive activation of cholinoreceptors due to OVERmedications.(TOPNOTCH)Robbins Basic Pathology, 8th ed. p.18

Question 16

Rivastigmine is a cholinomimetic (indirect-acting)

Answer 16

MOA: Inhibits acetylcholinesterase and amplifies endogenouly released acetylcholine. Uses: Alzheimer’s disease. (TOPNOTCH)Robbins Basic Pathology, 8th ed. p.18

Question 17

Treatment of Organophosphate poisoning.

Answer 17

Atropine and Pralidoxime

Question 18

Atropine is a Cholinergic antagonist (muscarinic). MOA: completely blocks all muscarinic receptors.

Answer 18

USES: Mydriatic, Cyclopegic, Antidote for organophosphate poisoning (first choice) and Bradycardia. SE: Tachycardia, Mydriasis, Cyclopegia,Delirium, Hallucination

Question 19

Pralidoxime is a cholinesterase regenerator, Antidote. MOA: Binds phosporus of organophosphate. Breaks organophosphate bond with cholinesterase.

Answer 19

Uses: Antidote for organophosphate poisoning and nerve gas poisoning. Notes: must be administered before 6-8 hours of organophosphate bond with cholinesterase occurs

Question 20

Benztropine is a cholinergic antagonist (muscarinic). MOA: completely blocks all muscarinic receptors. Restores neurotransmitter balance in the basal ganglia.

Answer 20

Uses: Parkinson’s disease (tremors, bradykinesia)

Question 21

Ipratropium is a Cholinergic antagonist (muscarinic). MOA: Blocks muscarinic receptors in bronchial smooth muscle. Prevents vagal-stimulated bronchoconstriction.

Answer 21

Uses: Asthma, COPD. SE: Dry mouth, Cough, Nasal dryness. Notes: more effective and less toxic than beta-agonists in patients with COPD and heart disease.

Question 22

Why is Ipratropium thye preferred bronchodilator in patients with comorbid COPD anf heart disease?

Answer 22

Less likely to cause Tachycardia and cardiac arrhythmias.

Question 23

Scopolamine is a Cholinergic antagonist (muscarinic). MOA: completely blocks all muscarinic receptors. Antagonizes histamine and serotonin.

Answer 23

Fatty Change(TOPNOTCH)Robbins Basic Pathology, 8th ed. p.23

Question 24

Atropine Toxicity: HOT as a hare, DRY as a bone, RED as a beet, BLIND as a bat, MAD as a hatter

Answer 24

Fever, Flush, Decreased secretions, Blurred vision, CNS toxicity, Tachycardia, Arrhythmias, Constipation

Question 25

Hexamethonium is a Cholinergic antagonist (nicotinic). MOA: Completely blocks Nn nicotinic Ach receptors.

Answer 25

Uses: Hypertension (obsolete). SE: Postural hyppotension, Dry mouth,Blurred vision.