CHOLINESTERASE INHIBITORS AND ANTICHOINERGICS Flashcards
Cholinergic agonists moa
Bind to cholinergic receptors and mimic the actions of acetylcholine
also called parasympathomimetic drugs; copy parasympathetic nervous system
Anticholinesterase moa
Inhibit acetylcholinesterase enzyme (the enzyme that destroys acetylcholine). This increases acetylcholine levels at the receptor sites and prolonging its effects.
Examples of cholinergic agonists
Bethanechol
Carbachol
Cevimeline
Pilocarpine
cholinergic Pharmacokinetics administration forms and how are they excreted?
Action and metabolism vary widely
Administered topically, orally, and subcutaneously
No I/V or I/M because rapid break down and rapid actions leads to crisis
Metabolized at the muscarinic and nicotinic receptor sites in the plasma and liver
Excreted by the kidneys
Cholinergic drugs
Pharmacodynamics COMMIT to memory
Mimic (copy) the actions of acetylcholine
Combine with the receptors on the target organs’ cell membranes
Actions
Salivation, slow heart rate, dilation of blood vessels, constriction of bronchioles , increase gut activity, contraction of urinary bladder and constriction of pupil
Cholinergic drugs Pharmacotherapeutics:
Cholinergic agonists are used in the following conditions
Urinary retention due to weak or atonic bladder
Lack of bowl movements especially post op period
Glaucoma to reduce intraocular pressure
Salivary gland hypofunction
cholinergic drug
Drug interactions
Other cholinergic drugs leads to toxicity
Cholinergic blocking agents
Quinidine
Cholinergic drugs:
Adverse reactions (wet as ocean)
7 things
Decrease heart rate* and lower BP
Nausea/vomiting
Increased activity of gut cramping and diarrhea
Excessive sweating/salivation
Increase urination
Blurred vision due to pupillary constriction
Shortness of breath due to bronchoconstriction
ACH
Acetylcholine applies breaks on heart but accelerates gut and bladder smooth muscles
Anticholinesterase drugs MOA
Block action of enzyme acetylcholinesterase , preventing breakdown of acetylcholine
This increases levels of acetylcholine are receptor sites leads to more stimulation by acetylcholine
Anticholinesterase drugs can be divided into two groups
Reversible- short duration of action; examples- physostigmine
Irreversible- long-lasting effects; examples- insecticides, nerve gas for warfare
Cholinergic drugs: Anticholinesterase drugs
pharmacokinetics
Absorbed from GI tract, subcutaneously, and mucous membranes
Can cross blood-brain barrier
Metabolized by enzymes in plasma
Excreted by the kidneys
cholinergic drugs: anti cholinesterase pharmacodynamics
Produce a stimulant or depressant effect on cholinergic receptors based on site, dose, and duration of action
Anticholinesterase drugs
Pharmacotherapeutics/ Indications
Glaucoma to reduce eye pressure
To increase bladder motility
To increase tone and motility of GI tract in patient with post op low gut motility ( paralytic ileus)
To improve muscle strength in myasthenia gravis
Antidote for cholinergic blocking agents
To treat dementia in Alzheimer’s’ disease (Alzheimer’s disease is due to deficiency of acetylcholine in brain)
when do we put scopolamine on
dont touch it, wash your hands, put it on in PRE op. take it off after 3 days.
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Cholinergic drugs: Anticholinesterase drugs
Adverse effects
Cardiac arrhythmias Nausea/vomiting Diarrhea Shortness of breath, wheezing Headache, seizures
best drugs to dry up secretions
rybinol
Cholinergic blocking agents/Anticholinergic Drugs
how do they act?
what are some examples?
are they competitive or noncompetitive antagonist
Interrupt parasympathetic nerve impulses in the central and autonomic nervous systems
Examples– atropine, belladonna, scopolamine
Atropine competes with acetylcholine for receptor sites – competitive antagonist
hr 58
hr 30
58- glycol
30- atropine
Cholinergic blocking agents pharmacokinetics
Pharmacokinetics
Absorbed through GI tract, eyes, mucous membranes, skin
Crosses blood-brain barrier
Metabolized in liver; excreted by kidneys
cholinergic
Pharmacodynamics
Stimulating or depressing effects depending on target organ and disorder
Cholinergic BLOCKING agents Pharmacotherapeutics / Indications. what do they do to the smooth muscles of the GI and Urinary bladder?
All cholinergic blocking agents relax smooth muscles of GI and urinary bladder. Therefore these are used in
Hyperactive bladder (e.g. Detrol ®)
Hyperactive gut (colic/ irritable bowel syndrome)
Biliary colic
Before endoscopy or sigmoidoscopy to relax GI smooth muscles
reglan- in class discussion who do we not give it to?
bowel obstruction!
when is Atropine give
is given before surgery to dry up secretions
To speed up heart rate during bradycardia *
To dilate pupil for eye exam
As an antidote for pesticide poisoning; blocks DUMBELSS i.e. Diarrhea, Urination, Miosis, Bronchospasm, Bradycardia, Excitation of skeletal muscles, Lacrimation, Salivation (and abdominal cramps)
Cholinergic blocking agents drug interactions
Tricyclic and tetracyclic antidepressants
cholinergic blocking agents adverse reactions
Adverse reactions Dry mouth Decreased sweating Reduced bronchial secretions Blurred vision due to pupillary dilatation Confusion Tachycardia increase body temperature
Treatment: antidote
for cholinergic blocking agents
physostigmine
atropine greater than 10mg
hallucinations delirium and coma
atropine greater than 5mg
rapid heart rate, palpitations, marked dryness of mouth dilation fo pupil some blurring of near vision
atropine 0.5mg
slight cardiac slowing some dryness of the mouth inhibition of sweating
Muscarinic receptors are located in:
Heart
Salivary glands
GI smooth muscle
GU tract
anticholinergic drugs moa
Competitively antagonize the neurotransmitter (NT) acetylcholine (Ach) at cholinergic postganglionic sites.
Naturally occurring tertiary amine belladonna alkaloids are
Atropine and Scopolamine.