This document discusses cholinesterase inhibitors, which prevent the breakdown of acetylcholine and butyrylcholine neurotransmitters. It covers their classification into natural alkaloids, semisynthetic derivatives, and synthetic compounds. Cholinesterase inhibitors increase levels of acetylcholine and butyrylcholine in the synaptic cleft by inhibiting the acetylcholinesterase enzyme. Their therapeutic uses include treatment of glaucoma, Alzheimer's disease, myasthenia gravis, cobra bites, and belladonna poisoning. Common adverse drug reactions are nausea, increased salivation, flushing, and bronchospasm.

1. By : Mehrasa Nikandish
Subject : Pharmacology
University of Georgia
2020-2021

2. • Introduction
• Receptors
• Classification
• Mechanism of action
• Therapeutic uses
• Adverse drug reactions

3. • Cholinesterase inhibitors, also known
as anti-cholinesterase, are chemicals
that prevent the breakdown of the
neurotransmitter acetylcholine
or butyrylcholine.
• This increases the amount of the
acetylcholine or butyrylcholine in
the synaptic cleft that can bind
to muscarinic receptors, nicotinic
receptors and others.
Cholinesterase
inhibitors
Acetylcholinesterase
inhibitors
Butyrylcholinesterase
inhibitors

4. Acetylcholine
(ACH)
ACH
receptors
Nicotinic
receptors
Muscarinic
receptors

5. Natural
Alkaloids
• Atropine
• Hyoscine
(Scopolamine)
Semisynthetic
derivatives
• Atropine
methonitrate
• Homatropine
• Hyoscine butyl
bromide
• Ipratropium bromide
• Tiotropium bromide
Synthetic
compounds
:
1. quaternary comps. :
propantheline- oxyphenonium-
clidinium- isopropamide
2. tertiary amines: diclycomine-
valethamate- pirenzepine.
Cyclopentolate -
Tropicamide
oxybutynin –
flavoxate- tolterodine.
trihexyphenidyl (benzhexol)-
procyclidine - biperiden

6. Enzyme inhibition: inhibit the enzyme
acetylcholinesterase reversibly- results in greater
availability of ACH at its sites of action.
Presynaptic effects: in the absence of
nondepolarizing neuromuscular-blocking drugs,
administration of an anticholinesterase drug may
produce spontaneous contractions of skeletal
muscles.
Direct effects on the neuromuscular junction

7. 1. Eyes
• Glaucoma
• Pilocarpine or
physostigmine
Alzheimer’s disease
• Treatment:
cholinergic
replacement using
cholinesterase
inhibitors such as:
• Donepezil
• Rivastigmine
Myaesthenia Gravis
• Diagnosis:
edrophonium is used
forTensilon test.
• Treatment:
1. pyridostigmine
60-120 mg
2. Neostigmine 15
mg

8. Cobra bite
• Treatment :
• Neostigmine
• Pyridostigmine
Belladonna poisoning
• (atropine poisoning )
• Physostigmine 0.5-2
mg is used by IV route.

9. 1. Nausea, increased salivation, increased sweating
2. Flushing, Bradycardia
3. Bronchospasm
4. Abdominal pain, Diarrhea
5. Increased urination
6. At high doses: convulsions; skeletal muscle weakness
7. ADR on eyes when used as eye drops: Miosis, decrease
vision in Dim-light, Impaired accommodation.

10. 1. Termination of further exposure to the poison fresh air, wash the skin
and mucous memberanes with soap and water, gastric lavage according to
the needs.
2. Specific antidots: a) atropine b) cholinesterase reactivators
3. Supportive measures: maintain blood pressure, hydration, control of
convulsions with judicious use of diazepam.
4. Maintain patent airway, positive pressure respiration if it is falling.

12. • What are anticholinesterase
drugs used for?
Major contraindications to the use of
muscarinic agonists
A) postoperative abdominal distention
B) asthma
C) treatment of diminished salvation,
secondary to radiation
D) peptic ulcer
E) hyperthyroidism
Answer:
Reversal of
nondepolarizers
Answer: B-D-E