Unit 4: Cholinergic Agonists Flashcards
2 targets of drug action for cholinergic agonists
- Postsynaptic receptor
2. Acetylcholinesterase enzyme
Acetylcholinesterase does what?
Breaks down acetylcholine
Where are nicotinic and muscarunic receptors found?
- All autonomic ganglia have nicotinic receptors
- All neuromuscular junction receptors are nicotinic
- All parasympathetic target organs have muscarunic receptors
Cholinergic agonists are divided into the following 2 groups
- Choline esters
2. Alkaloids
The alkaloids are ______ derivatives. What is important to note regarding alkaloids and cholinesterases?
Plant
Cholinesterases do not metabolize alkaloids
BETHANECHOL indication
Urinary retention
Nicotine does what to nicotinic receptors?
It is a direct agonist
Nicotine indications
Used therapeutically to help patients stop smoking
Cholinergic agonists generally have what effects?
Muscarinic
Cholinesterase inhibitors are broken into what 2 groups? How are these groups related to solubility?
Reversible (water soluble)
Irreversible (lipid soluble)
The REVERSIBLE INHIBITORS are used to treat what diseases?
- Myasthenia gravis
2. Alzheimer’s dementia
The reversible cholinesterase inhibitors tend to end with what?
- STIGMINE
- NIUM
The irreversible cholinesterase inhibitors are referred to as
Nerve gases
What effect do cholinesterase inhibitors have on acetylcholine?
They increase acetylcholine
Activation of MUSCARINIC RECEPTORS:
Effect on the EYE
Miosis (constriction of pupil)
Activation of MUSCARINIC RECEPTORS:
Effect on the CV SYSTEM
Decrease heart rate
Activation of MUSCARINIC RECEPTORS:
Effect on the RESPIRATORY SYSTEM
Bronchial constriction, increased secretions
Activation of MUSCARINIC RECEPTORS:
Effect on the GI SYSTEM
Increased motility
Sphincter relaxation
Activation of MUSCARINIC RECEPTORS:
Effect on the GU SYSTEM
Relaxation of sphincters
Bladder wall contraction
Activation of MUSCARINIC RECEPTORS:
Effect on the GLANDS
Increased secretions
Cholinergic agonists act on:
Postsynaptic receptor—some on the muscarinic one, some on the nicotinic one
Cholinesterase inhibitors act on:
Breaking down cholinesterase and therefore increasing acetylcholine
Choline esters have what in their name?
-CHOL-
What is important to note about the lipid soluble cholinesterase inhibitors?
They rapidly cross all membranes, including the blood brain barrier
What is Myasthenia Gravis?
An immune disease causing a loss of acetylcholine receptors, resulting in muscle weakness
How does Alzheimer’s relate to acetylcholine?
There is a deficiency of cholinergic neurons
EDROPHONIUM is used to …
Diagnose myasthenia gravis
How does EDROPHONIUM work?
For patients with myasthenia gravis, the drug dramatically improves muscle strength
For patients without myasthenia gravis, it causes increased secretions and GI cramping from increased GI motility
What is NEOSTIGMINE used to treat?
Myasthenia gravis
What is PYRIDOSTIGMINE used to treat?
Myasthenia gravis
Why is EDROPHONIUM—and not NEOSTIGMINE OR PYRIDOSTIGMINE—used to diagnose (vs treat) myasthenia gravis?
It is short acting. NEOSTIGMINE and PYRIDOSTIGMINE are both longer acting than ERDOPHONIUM.
What drugs treat nerve gas poisoning?
PRALIDOXIME and ATROPINE
SLUDGE…
Salivation Lacrimation Urination Diaphoresis GI Upset Emesis
