Cholinergic Drugs: Muscarinic Agonists and Antagonists Lecture PDF and Cholinesterase Inhibitors Lecture PDF

Question 1

Bethanechol (urecholine) drug class and therapeutic uses (3)

Answer 1

-direct acting muscarinic agonist

• urinary retention
• GI paralysis

Question 2

Bethanechol (urecholine) oral vs SC dose

Answer 2

Oral dose must be 40x SC dose to produce equivalent effects because it is charged impeding absorption across GI tract

Question 3

Bethanechol (urecholine) ADR’s (2)

Answer 3

• very few
• can worsen cardiovascular symptoms in hypotensive patients
• high doses abdominal cramping and involuntary defecation

Question 4

Bethanechol (urecholine) contraindications (3)

Answer 4

• gastric ulcers
• intestinal obstruction
• recent surgery of bowel

Question 5

Cevimeline (exovac) function

Answer 5

Derivative of Ach actions similar to bethanechol, relieves xerostomia by allowing and promoting salivation

Question 6

Pilocarpine function

Answer 6

Topical therapy of glaucoma (outdated) or treatment of dry mouth from sjogren’s syndrome

Question 7

Acetycholine usage pharmacologically

Answer 7

Restricted due to acetycholiesterase destruction, lacks sensitivity and can stimulate all muscarinic and nicotinic receptors but is also rapidly destroyed by cholinesterases

Question 8

Symptoms of muscarinic agonist poisoning (6)

Answer 8

• profuse salivation
• lacrimation
• visula disturbances
• bronchospasm
• diarrhea
• bradycardia

Question 9

Atropine (atropen) drug class and mech of action

Answer 9

• anticholinergic muscarinic antagonist
• Competes to cause blockage of muscarinic receptors, no effect itself but prevents activation of muscarinic receptor by endogenous Ach and at high doses nicotinic receptors as well

Question 10

Atropine (atropen) dosage and action

Answer 10

• low doses decrease secretion of salivary, sweat, and bronchial glands
• moderate doses increase heart rate and mydriasis
• higher doses urinary tract interfere with voiding and decrease intestine tone
• high doses in stomach causes decreased acid secretion

Question 11

Atropine (atropen) therapuetic uses (4)

Answer 11

• preanasthetic meds
• opthalmic inducing mydriasis and parlysis of ciliary muscle
• can accelerate heart rate in bradycardia
• intestinal hypermotility reducing frequency of bowel movements and abdominal cramps

Question 12

Atropine (atropen) ADR’s (4)

Answer 12

• dry mouth
• blurred vision and photophobia (paralysis of ciliary muscle focuses for far vision)
• elevation of intraocular pressure
• urinary retention

Question 13

Scopolamine (hysoscine HBr) function

Answer 13

Muscarinic atnagonist like atropine but produces CNS sedation opposed to excitement and suppresses emesis and motion sickness

Question 14

Neostigmine (prostigmin) absorption

Answer 14

contains positive charge, cannot cross BBB, GI tract, or placenta and must be administered high dose oral or by injection

Question 15

Neostigmine (prostigmin) mech of action

Answer 15

Binds of AchE but rxn takes place extremely slowly tying up AchE and thus leaving Ach levels higher
This allows for identical muscarinic responses compared to the muscarinic agonists

Question 16

Depolarizing nerumoscular blockade

Answer 16

Refers to when excessive amounts of Ach often from taking blocking agents such as Neostigmine (prostigmin) reducing force of contraction and producing paralysis of respiratory areas

Question 17

Neostigmine (prostigmin) therapeutic use and mech of treatment

Answer 17

• myasthenia gravis
• prevents inactivation of Ach thereby intensifying effect of Ach at motor end plates, provides symptomatic relief with small dosage titrated upward until optimal level of muscle functioning has been produced

Question 18

Neostigmine (prostigmin ADR’s (3)

Answer 18

• excess salivation
• increased gastric secretion
• miosis

Question 19

Cholinergic crisis

Answer 19

Excessive activity of acetycholine causing respiratoyr suppression and

Question 20

Treatment of cholinergic crisis (2)

Answer 20

• IV atropine

- mechanical ventilation

Question 21

Physostigmine therapeutic uses (2)

Answer 21

• treatment of muscarinic antagonist poisoning

- glaucoma

Question 22

3 common cholinesterase inhibitors used in alzheimer’s disease

Answer 22

• donepezil
• rivastigmine
• galantamine

Question 23

Myasthenia gravis pathophys

Answer 23

disease characterized by muscle weakness and predisposition to rapid fatigue, common see difficulty swallowing, ptosis, and severe trouble breathing due to paralysis of respiratory muscles due to autoimmune antibodies against nicotinic II receptors on skeletal muscle, results in muscle weakness

Question 24

Myasthenia crisis

Answer 24

-patient may experience if inadequately medicated, characterized by extreme weakness caused by insufficient ach at the NMJ and will lead to death by paralysis of respiratory muscles unless cholinesterase inhibitor used

Question 25

Cholinergic crisis

Answer 25

Overdosage of cholinesterase inhibitor characterized by extreme weakness or frank paralysis, accompanied by signs of muscarinic stimulation and treated with respiratory support plus atropine

Question 26

Determining cholinergic from myasthenia criss

Answer 26

• History of meds can provide diff diagnosis
• If inadequate, use ultra short acting cholinesterase agent and if symptoms alleviated then myasthenic, if intesnivides then cholinergic