Drugs #3

Question 1

M1

Answer 1

activates myenteric plexus

Question 2

M2

Answer 2

decreases HR

Question 3

M3

Answer 3

contracts circular ciliary muscle, bronchiolar muscle, GI smooth muscle, bladder detrusor muscle, stimulates secretions of the GI tract, eccrine sweat glands, tear glands, salivary glands

Question 4

Nm

Answer 4

muscle cell nicotinic receptor

Question 5

Nn

Answer 5

neuronal nicotinic receptor

Question 6

Nicotine(Nicotrol, Nicorette)

Answer 6

Nicotinic Receptor Agonist
selective for Nn receptor,
- diffuse activation of central and peripheral nicotinic receptors
-clinical application limited to preparations for smoking cessation

Question 7

Succinylcholine (anectine)

Answer 7

Nicotinic Receptor agonist
blocks Nm receptor
-used clinically as muscle relaxant during endotracheal intubation
–stick on-when it is activated for too long-blocks action potential (counter intuitive)
-excessive acetylcholine can cause paralysis

Question 8

Acetylcholine

Answer 8

Binds: nicotinic and Muscarinic
rapidly hydrolyzed by acetyl and plasma cholinesterases
-NO therapeutic use

Question 9

Methacholine

Answer 9

• Hydrolyzed by acetylcholinesterase but hydrolysis is slowed
• longer duration of action than acetylcholine
• primary muscarinic effects
• used to diagnose bronchial hyperactivity in patients suspected of having asthma
• toxicity: bronchiolar constriction
• contraindicated in pts given beta blockers since antidote to overdose is B-agonist

Question 10

Carbachol

Answer 10

• more resistant to hydrolysis by acetylcholinesterases
• stimulates both muscarinic and nicotinic
• miotic agent-topical to reduce pressure in glaucoma
• intraocular injection to reduce pressure after cataract surgery
• side effects: excessive muscarinic and nicotinic activation, ie: bronchoconstriction, reduced cardiac conduction

Question 11

Bethanechol

Answer 11

Muscarinic selectivity

Resistant to hydrolysis by acetyl and cholinesterases

• lack of nicotinic effects
• selective action on muscarinic receptors of GI tract and urinary bladder—less activity in M2 receptors (heart)
• used to treat postoperative non-obstructive urinary retention, post partum urinary retention and neurogenic atony of the bladder
• toxicity: bradycardia, bronchoconstriction
• contraindications: asthma, peptic ulcer, bradycardia

Question 12

Muscarine

Answer 12

no clinical utility

• muscarinic poisoning causes parasympathetic activation
• treated with atropine-a muscarinic receptor antagonist

Question 13

Pilocarpine

Answer 13

• Pure muscarinic activity
• crosses bbb
• Has appreciable CNS effects
• use in dry mouth due to head and neck radiotherapy or Sjogren’s syndrome
• treatment of open and angle-closure glaucoma
• administer with care to pts taking b-blockers due to exacerbation of conduction slowing

Question 14

Where are acetylcholinesterases found?

Answer 14

NM junction and cholinergic synapses, RBCs

Question 15

Where are butyrylcholinesterase found?

Answer 15

plasma, glial cells, liver

Question 16

What does inhibition of cholinesterases do?

Answer 16

• muscarinic actions at autonomic effector targets
• nicotinic actions at autonomic ganglia
• nicotinic actions at motor end plate
• muscarinic and nicotinic actions in CNS

Question 17

Neostigmine

Answer 17

reversible cholinesterase inhibitor

• sits for a while before they get metabolize
• doesnt cross bbb
• helps with muscle weakness
• primarily at nmj
• toxins too much activation–>paralysis-excessive amount
  contraindication: intestinal obstruction

rx: myasthenia gravis
reversal of non-depolarizing neuromuscular blockade

Question 18

Edrophonium

Answer 18

shorter acting
-diagnose to determine has been given too much neostigmine–>if it is will make it worse

-diagnonsis of myasthenia gravis differential diaagnosis of too little or too much AchE inhibitor

Toxicity:bradycardia, cardiac standstill

Contraindication: intestinal blockade or urinary obstruction

Question 19

Physostigmine

Answer 19

Activity will last for a long time
-main use for musc antag poisoning
-can cross bbb
toxicity: convulsions, respiratory and CV depression
COntraindications: asthma, CV disease, intestinal obstruction

Question 20

Donepezil

Answer 20

inhibits only acetylcholinesterase

rx for alzheimer’s disease

Question 21

What are irreversible cholinesterase inhibitor?

Answer 21

organophosphates

Question 22

Toxicity of organophosphates

Answer 22

D diarrhea
U urination 
M miosis
B bradycardia
B bronchorrhea
E emesis
L lacrimation 
S salvation

Question 23

What is treatment for irreversible cholinesterase inhibitors?

Answer 23

1. ventilation
2. suction of tracheal secretions
3. antimuscarinic agent (atropine)
4. reactivation of acetylcholinesterase with Pralidoxime chloride (2-PAM)
   - if it hasn’t been allowed to age can restore it

Question 24

Echothiophate

Answer 24

irreversible acetylcholinesterase inhibitor used clinically

rx: long term miosis in the treatment of open angle glaucoma
- half-life is long, only requires 1x per day dosing

Question 25

Atropine

Answer 25

muscarinic antagonist

rx: organophosphate poisoning (insecticides and nerve gas)
- induction of mydriasis and cycloplegia
- reverse bradycardia of vagal origin
- reverse gastrointestinal hypermotility
- bladder spasms (urgency) associated with cystitis

Question 26

scopolamine

Answer 26

• highly toxic used in very small doses
  rx: nausea and vomiting associated with motion sickness or chemo
  tx: antimuscarinic actions, effects may be long-lived esp in adults

Question 27

glycopyrrolate

Answer 27

quaternary nitrogen muscarinic antagonist
-doesn’t cross bbb

Rx: used to protect against excessive muscarinic effects of cholinesterase inhibitors during reversal of neuromuscular blockade, pre-operative anti-sialogogue (no spit)

Tx: can cause heat stroke due to inability to sweat in heat

Question 28

atropine poisoning

Answer 28

opposite of dumbbel