Cholinergic Agents

Question 1

Pralidoxime

Answer 1

• Antimuscarinic, upregulates acetylcholinesterase to break down Ach at neuronal synapse.
• Used to treat organophosphate poisoning.
• SE: Anticholinergic (hot as a hare, blind as a bat, dry as bone, red as a beet, and tachycardia)

Question 2

Echothiophate

Answer 2

• Inhibits acetylcholinesterase; increase ACh at nicotinic and muscular junction.
• Wide angle glaucoma.
• SE: Cholinergic- DUMBELS (diarrhea, urination, miosis, bronchospasm, bradycardia, emesis, lacrimation, and salivation.

Question 3

Tacrine, Donepezil

Answer 3

• Inhibit acetylcholinesterase; increased stimulation at the nicotinic and muscarinic junction.
• Tx Alzheimer.

Question 4

Edrophonium and Pyridostigmine

Answer 4

• Inhibits acetylcholinesterase
• Edrophonium: diagnose myasthenia gravis (Ab to AChR); Tensilon Test
• Pyridostigmine: tx myasthenia gravis.

Question 5

Neostigmine

Answer 5

• Inhibits acetylcholinesterase.
• Tx myasthenia gravis. Stimulate GI tract and bladder; used by anesthiologists to overcome non-depolarizing neuromuscular blockade.

Question 6

Physostigmine

Answer 6

• Inhibits acetylcholinesterase.
• Tx atropine poisoning and glaucoma (causes miosis to stimulate outflow of aqueous humor from the eye; decreasing intraocular pressure).

Question 7

Oxybutinin

Answer 7

• Antimuscarinic. Muscarinic (M1, M2, M3)- receptor antagonist.
• Urinary incontinence.
• SE: Anticholinergic: hot as hare, blind as bat, red as beet, and dry as a bone, and tachycardias.

Question 8

Ipratropium and Tiotropium

Answer 8

• Muscarinic receptor antagonist. Blocks M3 (SM) –> bronchodilation.
• Tx for COPD and asthma.

Question 9

Benztropine

Answer 9

• Antimuscarinic. Can cross BBB to block M1: decrease cholinergic action on GABA.
• Adjuvant tx in Parkinson disease. Does not improve bradycardia.
• SE: causes mydriasis so contraindicated in glaucoma.

Question 10

Scopolamine

Answer 10

• Antimuscarinic.
• M1 block: motion sickness. M3 block: decreased GI motility and cycloplegia with mydriasis.
• SE: hot as hare, blind as bat, red as beet, and dry as a bone, and tachycardias.

Question 11

Atropine

Answer 11

• Antimuscarinic.
• Antidote for organophosphate nerve gas poisoning. Treatment of bradycardia during cardiac emergencies.

Atropine poisoning treated with physostigmine.

Question 12

Bethanechol

Answer 12

• M2 and M3 agonist. Promotes urination.
• Treat neurogenic and urinary retention in postpartum and postoperative period.
• SE: bradycardia and hypotension because it acts on M2 in the heart.

Question 13

Methacholine

Answer 13

• Muscarinic agonist.

- SM contraction of the bronchi; bronchial challenge test and used for diagnosis of reactive airways disease.

Question 14

Pilocarpine and Carbachol

Answer 14

• Muscarinic agonist

- Miosis to tx narrow and wide angle glaucoma.

Question 15

Muscarinic Agonists and Cholinesterase Inhibitors

Answer 15

• Muscarinic Agonists:
  Pilocarpine, Methacholine, and Bethanechol.
• Cholinesterase Inhibitors:
  Neostigmine, edrophonium and pyridostigmine, tacrine/ donepezil, echothiophate, organophosphate nerve gas.

Question 16

Antimuscarinic Agents and Cholinesterase Re-Activators

Answer 16

• Antimuscarinic Agents:
  Atropine, Scopolamine, Benztropine, Ipratropium, Oxybutynin.
• Cholinesterase Reactivators: Pralidoxime