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45 Cards in this Set

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What are the three major groups which classify drugs that block ACh receptors?
Neuromuscular blockers, ganglion blockers, and antimuscarinic blockers
Neuromuscular Blockers
-are antagonist at nicotinic ACh receptors in skeletal muscle tissue, part of the somatic nervous system
Ganglion Blockers
Antagonize nicotinic ACh receptors in the ganglia
Antimuscarinic Drugs
ACh receptor antagonist
What are the 2 naturally occuring antimuscarinic drugs?
Atropine and Scopolamine
What two plant sources can atropine be isolated from?
Atropa belladonna (deadly nightshade) and Datura stramonum (jimsonweed)
How does Atropine occur in nature relative to commerical purposes?
In nature, Atropine occurs as a single enantiomer, but when isolated for commercial purposes it forms a racemic mixture.
When Atropine is in its natural, single enantiomer state, what is referred to?
Hyoscyamine
What is the synthetic derivative that is very similar in chemical structuire to the naturally occurring atropine and scopolamine?
Homatropine
Quaternary Amine Antimuscarinics
1. Have a permanently charged nitrogen atom that increases the overall polarity relative to the tertiary amine antimuscarinics.
2. Have more peripheral effects
TRUE/FALSE. Polar drugs distribute well to the CNS.
FALSE. Polar drugs DO NOT distribute well to the CNS
Name 3 Quaternary Amine antimuscarinic drugs.
Ipratropium, Tiotropium, and Trospium Chloride
Tertiary Amines
1. Have more CNS effects
2. Less polar then quaternary amine antimuscarinics
Name the 6 Tertiary Amine Antimuscarinic drugs.
Benztropine, Dicyclomine, Oxybutynin, Tolterodine, Darifenacin, Solifenacin "SOB DDT"
TRUE/FALSE. Synthetic antimuscarinic analogs tend to have less selectivity to muscarinic ACh receptors.
TRUE. Synthetic antimuscarinic analogs tend to have less selectivity to muscarinic ACh receptors.
What should be used when a patient has cholinergic poisoning?
With cholinergic poisoning, both CNS and PNS toxicity must be reversed. Atropine is extremely useful as an antidote for life-threatening toxicity secondary to nerve gas or insecticides (in both cases, typically an organophosphatase acetylcholinesterase inhibitor)
Why are quaternary amine antimuscarinic drugs not used for cholinergic poisoning?
Therefore, antimuscarinic agents that are quaternary amines must not be used for this purpose, because they don't distribute to the CNS due to the polar nature secondary to their permanently charged state.
What effects do the antimuscarinics have on the eye?
-They block M3 receptors in the eye resulting in
1. Cyclopegia (paralysis of the ciliary muscle leading to loss of ability to focus
2. Mydriasis (pupil dilation due to loss of pupillary constrictor muscle activity on the iris)
When are cyclopegia and Mydriasis desired?
During an ophthalmic exam
Name 3 examples of antimuscarinic drugs which are used for the eye examinations?
Atropine, Homatropine, and scopolamine
What effects do the antimuscarinics have on the cardiovascular system?
Blockade of muscarinic (M2) ACh receptors in the heart leads to loss of vagal slowing of the heart rate.
Positive Chronotrophic effect (increase in heart rate)
What is the major cardiovasuclar use of atropine?
The major use of atropine is for acute treatment of sinus bradycardia, particularily in life-threatening situations such as myocardial infarction.
What effects do antimuscarinics have on the respiratory tract?
Broncodilation and a reduction in respriatory secretion in patients with airway diseases such as COPD by blockade of M3 postsynaptic receptors.
What 2 drugs are used most often for respiratory diseases?
Ipratropium and Tiotropium
What is commonly used in the management of asthma?
Aerosolized delivery of ipratropium, often in conjunction with Albuterol (a beta-adrenergic agonist)
What is used for the reduction of bronchial secretions secondary to the use of general anesthetic agents?
Ipratropium
What effects do the antimuscarinics have on the GI tract?
-Secretory activity is supressed, resulting in significant reduction in saliva production leading to dry mouth.
-Gut motility is decreased secoondary to relaxation of GI smooth muscle tissue
-Overall, this has an antidiarrheal effect which may lead to constipation
Which two drugs in combination have been used extensively for the treatment of mild to moderate diarrhea?
Atropine in combination with Diphenoxylate (an opioid antidiarrheal agent)--> brand name Lomotil. The inclusion of Atropine is mostly for the benefit of preventing abuse of the opioid diphenoxylate.
What effects do antimuscarinics have in the Gentitourinary Tract?
-Antagonism of M3 ACh receptors results in:
1. relaxation of smooth muscle in the urinary bladder and
2. Ureter contraction of the urinary sphincter.
-Overall, this leads to decrease in urinary bladder urgency and voiding frequency, improvement of urinary incontinence, and an increase in urinary retention.
The effects of antimuscarinics on the Gentitourinary tract are useful for the management of?
Mild to moderate urinary bladder spasm secondary to surgery, inflammation, or other neurologic conditions, such as neurogenic bladder (often referred to as overactive bladder)
Name the 5 antimuscarinic drugs useful for an overactive bladder.
Oxybutynin, Tolterodine, darifenacin, solifenacin, and trospium chloride.
Which antimuscarinic drug is selective for M3 receptors, why is this impt.?
Darifenacin is selective for M3 receptors, and therefore may have less antimuscarinic-related adverse effects due to lack of blockade of other muscarinic receptor subtypes.
What effects do the antimuscarinics have on the CNS at usual doses?
-At usual doses, antimuscarinic agents (tertiary amines ONLY) have long-lasting sedative effects in the CNS, causing drowsiness and somnolence.
What effects do the antimuscarinics have on the CNS at high and toxic doses?
Antimuscarinic drugs (tertiary ONLY), may cause tremor, delirium, and hallucinations
What are the symptoms of Parkinson's disease attributed to? What is one way to manage this disease?
The symptoms of Parkinson's disease are due, in part, to an excess of ACh activity relative to dopamine activity in the CNS.
-One way to manage this disease is to use centrally-acting antimuscarinic agents to decrease ACh activity.
What antimuscarinic drug has been used for the management of Parkinson's disease?
Benzotropine
What is the old saying regarding typical antimuscarinic side effects, that summerizes the major adverse effects?
Dry as a bone, blind as a bat, red as a beet, mad as a hatter. This saying is referring to the adverse effects of dry mouth, cyclopegia, hot and flushed skin, and the delirium and hallucinations that accompany large doses of antimuscarinic drugs.
Name 6 typical antimuscarinic adverse effects:
dry mouth, urinary retention, erectile dysfunction, constipation, and sedation
TRUE/FALSE. Use of the antimuscarinic agents needs to be carefully considered in patients for which of the adverse effects may exacerbate existing disease states.
TRUE. For example: antimuscarinic-induced urinary retention would make symptoms of prostatic hypertrophy worse.
The use of antimuscarinic should be carefully considered in? Why?
Pediatric and geriatric populations.
Why should antimuscarinics be carefully considered in pediatric patients
Mainly for the increased sensitivity in children to antimuscarinic-induced hyperthermia
Why should antimuscarinics be carefully considered in geriatric patients?
Mainly for the increased sensitivity in geriatrics to constipation and genitourinary adverse effects.
What may be given if anitmuscarinic poisoning occurs?
In severe cases, the use of a AChE inhibitor, such as physotigmine or neostigmine.
What drug interaction could occur with antimuscarinics?
Medications that also have significant anticholinergic effects. For example, Amitriptyline, a tricyclic antidepressant with anticholinergic adverse effects, would be expected to add to dry mouht, constipation, and genitourinary adverse effetcs that a patient is experiencing from an antimuscarinic drug.
Name 12 antimuscarinic drugs.
Atropine, benztropine, darfenacin, dicyclomine, Homatropine, Ipratropium, Oxybutynin, Scopolamine, Solifenacin, Tiotropium, Tolterodine, and Trospium Chloride
"T SAID BOTH STD"