Overview
•- Indirect cholinergic agonism (AchE
inhibition)
•- Muscarinic antagonism (emphasis on
drugs and organ effects)
•- Nicotine-Ach receptor (emphasis on
drugs and therapeutics)
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Guidelines and tips
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Acetylcholine Inhibitors and Muscarinic Antagonists: Mechanisms, Uses, and Antidotes, Lecture notes of Pathophysiology
An overview of indirect cholinergic agonists, focusing on acetylcholine esterase inhibitors and muscarinic antagonists. It covers the mechanisms of indirect agonism, the effects and therapeutic uses of these inhibitors, and the role of muscarinic antagonists. The document also includes information on the history and sources of relevant drugs, their effects on the body, and antidotes.
Typology: Lecture notes
2014/2015
1 / 27
This page cannot be seen from the preview
Don't miss anything!
Related documents
Partial preview of the text
Download Acetylcholine Inhibitors and Muscarinic Antagonists: Mechanisms, Uses, and Antidotes and more Lecture notes Pathophysiology in PDF only on Docsity!
Overview
- Indirect cholinergic agonism (AchE
inhibition)
- Muscarinic antagonism (emphasis on
drugs and organ effects)
- Nicotine-Ach receptor (emphasis on
drugs and therapeutics)
Indirect cholinergic agonists
Inhibitors of acetylcholinesterase
Increase acetylcholine concentration and lifetime by
inhibiting degradation
Act by binding to AchE active site causing reversible
(non covalent) or long lasting (covalent modification)
AchE Inhibitors (quaternary alcohols and
carbamates)
Organophosphates
Organ effects/therapeutic uses
- Effects are due to acetylcholine accumulation and are
both sympathetic and parasympathetic
USES Approx Duration
ALCOHOLS
Edrophonium Myasthenia gravis 5 – 15 minutes
arrythmias
CARBAMATES
Neostigmine Myasthenia gravis 0.5 – 2h
Pyridostigmine Myasthenia gravis 3 – 6h
Physostigmine Glaucoma 0.5 – 2h
Demecarium Glaucoma 4 – 6h
Organophosphates
Echotiophate Glaucoma 100 h (> 4 days)
Treatment of organophosphate poisoning
1 - maintenance of vital signs (respiration particularly
important)
2 - Decontamination (to avoid further absorption)
3 - Atropine parenterally (to minimize muscarinic effects)
as required
4 - Rescue of AchE activity with Hydroxylamines
(Pralidoxime, Diacetylmonoxime)
Muscarinic Antagonists
ATROPINE
SCOPOLAMINE
Muscarinic Antagonists
ATROPINE
SCOPOLAMINE
Attropa belladona
- Atropine and Scopolamine are belladona alkaloids
(competitive inhibitors)
- Drugs differ in their CNS effects, scopolamine permeates the
blood-brain barrier
- At therapeutic doses atropine has negligible effects upon the CNS,
scopolamine even at low doses has prominent CNS effects.
History/sources
- Atropa belladona - used in the renaissance
- Deadly nightshade - used in the middle ages to produce prolonged
poisoning
Jimson plant leaves burned in India to treat Asthma (1800) purification
of atropine (1831)
Effect of muscarinic inhibitor in the eye
Pupil dilation vs accomodation
Graphic summary of atropine effects
Organ effect – drug review
Antidotes
ORGAN DRUG APPLICATION
CNS Benztropine Treat Parkinson’s disease
Scopolamine Prevent/Reduce motion sickness
Eye Atropine Pupil dilation
Bronchi Ipatropium Bronchodilate in Asthma, COPD
GI Methscopolamine Reduce motility/cramps
GU Oxybutinin Treat transient cystitis
Postoperative bladder spasms
Nicotinic – Acetylcholine Receptor
polarized
Relaxation
depolarized
contraction