Cholinergic pharmacology Flashcards
Preganglionic ACh binds to
Nicotinic receptors
Postganglionic ACh binds to
Muscarinic receptors
How is ACh made inside cell
Choline + Acetyl CoA with help of choline acetyltransferase
What degrades ACh in the cell
Acetylcholinesterase
Acetylcholinesterase inhibitors
Blocks degradation of ACh causing an excess of ACh in synapse–will indirectly over stimulate N and M receptors on post ganglionic cell
Vesamicol
blocks vesicle formation of ACh which will block ACh release and block receptor stimulation for N and M
Hemicholinium
blocks choline uptake so ultimately decreases formation of ACh
Botulinum toxin
Prevents ACh release
Used specifically to block Nm receptors in blepharospasm, strabismus, dystonia, achalasia
Used to block M receptors in excessive sweating (hyperhydrosis)
M receptor activation leads to
Decreased HR, increased secretions, and increased smooth muscle contraction
All effects of M receptor activation
Eye pupil constriction, accommodation for near vision, bradycardia, bronchospasm, increased GI motility, increased voiding, dilation of blood vessels, increase in all gland secretions
Most common side effects of muscarinic agonists
Excessive sweating and GI distress
Methacholine
Muscarinic agonist used for an asthma challenge–see how much bronchospasm occurs
Bethanechol
Muscarinic agonist used for urinary retention treatment
Carbachol
Muscarinic agonist used for glaucoma treatment by causing pupil constriction
Rivastigmine
Central acting AChE inhibitor used for alzheimer’s disease
Donepezil
Central acting AChE inhibitor used for alzheimer’s disease
Edrophonium
Short acting AChE inhibitor used to diagnose myasthenia gravis vs cholinergic crisis
If patient has myasthenia gravis, giving the drug will cause increased muscle tone
If patient is having a cholinergic crisis, patient will still experience flaccid paralysis
Neostigmine
longer acting AChE inhibitor used to treat myasthenia gravis
Physostigmine
Used to life threatening anticholinergic toxicity such as atropine overdose
Irreversible AChE inhibitors
Organophosphates
See with farmers overdose
muscarinic and nicotinic effects of acute AChE inhibitor toxicity
Diarrhea Urination Miosis Bradycardia Bronchoconstriction Excitation of CNS and muscle Lacrimation Salivation Sweating
Treatment for acute toxicity of AChE inhibitor
Atropine
Other drugs that have anti-muscarinic effects
Antihistamines, TCA’s, antipsychotics, quinidine, amantadine, meperidine
Pharmacologic effects of atropine
Anti-muscarinic Dry mouth Blurry vision and dilated pupils Hyperthermia (hot and dry skin) Tachycardia Sedation Urinary retention and constipation Behavioral excitation and hallucination
Cardinal signs of anti-muscarinic drugs
blurry vision and dry mouth
Tropicamide
Anti-muscarinic
Used in ophthalmology to dilate pupils
Ipratropium
Anti-muscarinic
Used for asthma to decrease bronchospasm
Tiotropium
Anti-muscarinic
Used for COPD
Scopolamine
Anti-muscarinic
Used for motion sickness by causing sedation
Pilocarpine
Increase mouth secretions for dry mouth
Cholinimimetics
Signs of AChE inhibitor toxicity
DUMBBELSS–Diarrhea, urination, miosis (pupil constriction), bronchospasm, bradycardia, sweating, salivation, lacrimation, flaccid paralysis (Due to nicotonic activation)
Pralidoxime
Reverses organophosphate toxicity by bringing back AChE
Oxybutynin
Decrease urinary flow
Used to treat overactive bladder and urinary incontinence
Tolterodine
Decrease urinary flow
Used to treat overactive bladder and urinary incontinence
Benztropine
Anti muscarinic used to treat Parkinson symptoms (decreased dopamine can lead to overactive Ach)
Trihexyphenidyl
Anti muscarinic used to treat Parkinson symptoms (decreased dopamine can lead to overactive Ach)
side effects of anti muscarinic
Opposite of DUMBBELSS
Hot (Due to decreased sweating), vision problems due to decreased accommodation and dilation, increased HR, decreased aqueous humor causing increased eye pressure, decreased secretion causing dry mouth, CNS effect causing madness
