Cholinergic Antagonists

Question 1

Atropine

Answer 1

M»N

• to reverse intense parasympathetic activation (insecticide)
• also used pre op to minimize respiratory and gastric secretions
• eyes (dilation)
• oral effects: salivation>micturition>eye>HR

Question 2

Hexamathonium

Answer 2

Nn selective (ganglionic blocker)
Nn>Nm»M
- Nn in both systems (sympathetic and parasympathetic)
- Heart will keep beating (intrinsic excitation)
- arterioles (no parasympathetic so inhibits sympathetic and get dilation, drop BP, block baroreceptor (requires both arms of ANS), controlled hypotension to prevent massive drop by body)

Question 3

Tubocurarine

Answer 3

Nm selective (neuromuscular blocker)
Nm>Nn»M
- induce flaccid paralysis
- initial switch from excitation