pharmacology: cholinergic drugs Flashcards Preview

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Flashcards in pharmacology: cholinergic drugs Deck (31):
1

where are M2 receptors? what is their mechanism?

SA and AV node
Gi coupled; decreased cAMP

2

where are the M1 receptors? M3 receptors? what is their mechanism?

M1: glands in the GI tract
M3: everywhere else essentially
Gq coupled: increased phospholipase C --> increased IP3, DAG, and Ca2+

3

botulinum toxin mechanism

interacts with synpatobrevin and other proteins to prevent ACh release - used in blepharospasm, strabismus/hyperhydrosis, dystonia, cosmetics

4

what has no innervation but has M3 receptors? what are the implications of this?

blood vessels - M3 leads to NO release (vasodilation)
means there will be no effects of indirect agonists

5

what are the muscarinic agonists?

Ach, bethanechol, methacholine, pilocarpine

6

Ach clinical uses

short half-life so no clinical use

7

bethanechol clnical use

ileus (postop/neurogenic), urinary retention

8

methacholine clinical uses

diagnositic procedure - bronchial hyperreactivity

9

pilocarpine use

topically used for glaucoma, xerostomia

10

what receptors can cause flaccid paralysis?

NN and NM because desensitized very quickly

11

NN and NM mechanisms

activation (opening) of Na/K channels

12

what are the indirect-acting cholinomimetics?

acetylcholinesterase inhibitors:
edrophonium, physostigmine, neostigmine, pyridostigmine, donepezil, organophosphates (echothiphate, malathion, parathion)

13

edrophonium: characteristics and clinical uses

characteristics : short acting
clinical uses: diagnose myasthenia and used to differentiate myasthenia from cholinergic crisis (desensitization)

14

physostigmine: characteristics and clinical uses

characteristics: tertiary amine (enters CNS)
clinical uses: glaucoma, antidote in atropine overdose

15

neostigmine and pyridostigmine: characteristics and clinical uses

characteristics: quaternary amines (no CNS entry)
clinical uses: ileus, urinary retention, myasthenia, reversal of nondepolarizing NM blockers

16

donepezil: characteristics and clinical uses

characteristics: lipid soluble (CNS entry) - oral form!!
clinical uses: alzheimer's

17

organophosphates (echothiophate, malathion, parathion, sarin): characteristics and clinical uses

characteristics: lipid-soluble, IRREVERSIBLE INHIBITORS (non competitive)
clinical uses: glaucoma (echothiophate eyedrops)
insecticides (malathion, parathion), nerve gas (sarin)

18

where can acetylcholinesterase inhibitors NOT be used?

blood vessels

19

acute toxicity of AChE inhibitors

excessive muscarinic and nicotinic stimulations
muscarinic effects: diarrhea, urination, miosis (pinpoint pupil), bradycardia, bronchoconstriction, lacrimation, salivation, sweating, CNS stimulation
nicotinic effects: skeletal muscle excitation followed by paralysis (cholinergic crisis), CNS stimulation

20

management of AChE inhibitors

atropine (muscarinic blocker); regeneration of AChE: pralidoxime (2-PAM)

21

chronic toxicity of AChE inhibitors

peripheral neuropathy causing muscle weakness and sensory loss d/t demyelination not due to AChE inhibitors (no treatment)

22

what are the muscarinic receptor antagonists?

atropine, tropicamide, ipratropium, triotropium, scopolamine, benztropine, trihexyphenidyl

23

atropine: characteristics and clinical uses

characteristics: tertiary amine (enters CNS)
clinical uses: antispasmodic, antisecretory, management of AChE inhibitors overdose, antidiarrheal, ophthalmology (long action)

24

pharmacologic effects of atropine

decreased secretions, mydriasis, cycloplegia, hyperthermia, tachycardia, sedation, urinary retention and constipation, excitation and hallucinations (mimics alzheimer's)

25

what are classes of drugs with antimuscarinic pharmacology

antihistamines, tricyclic antidepressants, antipsychotics, quinidine, amantadine, meperidine

26

what is used for treatment of acute intoxication of antimuscarinics

physostigmine

27

tropicamide clinical uses

ophthalmology (topical)

28

ipratropium and tiotropium clinical uses

asthma and COPD (inhalational) - no CNS entry, no change in mucus viscosity (decreased secretions)

29

scopolamine clinical uses

used in motion sickness, causes sedation and short-term memory block (affects CN8 most)

30

benztropine and trihexyphenidyl clinical uses

lipid-soluble (CNS entry) used in parkinsonism and in acute extrapyramidal symptoms induced by antipsychotics

31

what are the ganglion blocking agents (nicotinic recptor antagonists)

hexamethonium and mecamylamine (preduce the predominant autonomic tone) --> prevent baroreceptor reflex changes