Cholinergic Antagonists

Question 1

Antimuscarinic Agents MOA

Answer 1

Relatively non-selective.
=Competitive, reversible antagonists of ACh at muscarinic receptor sites.
Marked affinity for muscarinic receptors, but no intrinsic activity.
ex. Atropine and scopolamine (eye)

Question 2

Atropine Effects on Secretions

Answer 2

• reduction in salivary secretions

- reduction in sweating…Atropine Fever

Question 3

Atropine Effects on Respiratory System

Answer 3

-reduction of bronchial spasm and secretion

Used as adjunct to bronchodilation therapy (Ipratropium (Atrovent) , Tiotropium)

Question 4

Atropine Effects on Eyes

Answer 4

Used during Eye Exams
-Mydriasis
-Cycloplegia (no accommodation for near vision)
-Reduced lacrimal secretions
=Tropicamide is used because recovery is 2-6 hrs (vs. atropine recovery up to 10 days)

Question 5

Atropine Effects on Heart

Answer 5

Increased heart rate

Question 6

Atropine Effects on Blood Vessels

Answer 6

** Vasodilation **
“atropine flushing”, redness
(counterintuitive but it is what it is)

Question 7

Atropine Effects on Bladder

Answer 7

-reduced urination (micturation)
-reduced bladder spasm (rx: overactive bladder)
=oxybutyin, tolterodine (older drugs)
=darifenacin, solifenacin (newer and more selective for M3= fewer side effects)

Question 8

Atropine Effects on GI Tract

Answer 8

-reduced GI motility and spasm
-reduced gastric acid secretions
= dicyclomine, glycopyrrolate

Question 9

Atropine Effects on CNS

Answer 9

• sedation
• prevention/rx of motion sickness
• reduce sx of drug-induced parkinsonism tremors
• delirium, confusion, memory loss

Question 10

Atropine Adverse Reactions

Answer 10

Hyperthermia 
Dry Mouth, Eyes, Mydriasis, BLURRED vision 
(Don't take if dx with glaucoma!!!) 
Tachycardia
Hot and flushed Skin 
Agitation, Delirium 
Constipation + Urinary Retention

Question 11

Anti-nicotinics - Ganglionic Blockers MOA

Answer 11

Trimethaphan is a non-depolarizing (competitive) blocker. It binds to the ACh nicotinic receptor site, but has no intrinsic activity.
=Trimethaphan (Hexamethonium)

Question 12

Anti-nicotinics - Ganglionic Blockers Side Effects

Answer 12

CVS sedation
hypOtension
loss of accommodation
loss of thermoregulatory sweating

Question 13

Atropine Poisoning

Cause, Symptoms, Treatment

Answer 13

Bella donna or Deadly Night Shade. Foliage and berries are extremely toxic.
Blind as a Bat, Dry as a Bone, Hot as a Hare (fever), Red as a Beat (flushing), Mad as a Hatter, (+) constipation, urinary retention, tachycardia
Rx: Phyisostigmine (AChE inhibitor, crosses BBB), pump stomach