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10 Cards in this Set
- Front
- Back
What are antimuscarinics?
Mechanism of action |
1. Decrease ACh action
2. Bind post-synaptic muscarinic receptors competitively inhibiting ACh. Antiparasympathetic or parasympatholytic(competitive antagonist) |
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What are the effects of antimuscarics?
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Opposite of PSNS stimulation, & depend on cholinergic tone.
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Atropine & Scopolamine
Which receptors are they selective for? Which crosses the BBB? Side effects? |
Selective for muscarinic vs. nicotinic but NOT subtypes
-Multiple side effects Selectivity by local administration Scopolamine crosses BBB easily & Atropine only at high doses. CNS effects: depression, amnesia, excitation, & hallucination.(more with scopalamine due to BBB) |
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Therapeutic Uses for Antimuscarinics
-Use for the mouth? -Use for the eye? Which drugs?Which muscles? -Pre & Post surgery use? |
-Reduces saliva production:Atropine
-Dilates pupil for opthalmological exam:Tropicamide relaxes sphincter muscle, short acting. Tropicamide+phenylephrine = an alpha-adrenergic agonist to contract radial muscle for complete dilation. -Prior: Block parasympathetic impulse to the heart(vagal slowing) preventing cardiac shutdown(NOT for patients risking cardiac slowing such as Down's synd)/Post: prevents muscarinic side effects of ChE-Inhibitor & used to reverse muscle block. |
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Cholinesterase Inhibitor Intoxication
-Effects of Organophosphate poisoning? -Therapeutic goal? -Drugs? |
-Muscarinic, Nicotinic, CNS effects
-M: miosis, salivation sweating bronchial constriction & secretions -N: weakness, twitching, muscle weakness & paralysis -C: convulsions, coma, respiratory paralysis -Block all Muscarinic receptors & reactivate ChE -HIGH DOSE atropine/ChE reactivator = Pralidoxime: breaks bond holding cholinesterase to ChE BEFORE aging (w/in 24 hrs) |
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Urinary urgency & frequency
-Drugs? -Used for which populations? |
-Tolterodine: selective for detrusor muscle relaxation & internal sphincter tightening.
-SOLIFENACIN: M3 agonist, more effective than tolterodine, less dry mouth problem -Incontinence in adults, bed wetting in kids -Few side effects |
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Motion Sickness
Drugs? Side effets? |
-Scopolamine: given prophylactically as a path or oral.
-Dry mouth, drowsiness, sometimes blurred vision. |
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Bronchospasm(Asthma, COPD)
Drugs? Effect? |
-IPRATROPIUM: non-selective muscarinis antagonist for inhale.
TIOTROPIUM: receptor antagonist, 24 hr duration, selective for M1 & M3 -Bronchodilation & reduced secretion, local effect via direct inhalation. |
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Parkinsonism
Cause? Drugs?Side effects? Contraindications? |
-LOSS of dopaminergic neurons
-Net increase in ACh excitation -Antimuscarinics play a secondary role now. -LEVODOPA & CARBIDOPA -CNS effects increase w/ age -Any condition with impaired PSNS function |
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Antimuscarinic toxicity
-Sources of toxicity? -Symptoms? -Treatment? |
-Plants: eat common weeds, Drugs w/ atropine-like agents: antihistamines, phenothiazine, tricyclic's. Ingestion of antidiarrheal drug = lomotin in chilren
-Blind as a bat, dry as a bone, red as a beet, hot as a hare, mad as a hatter. -Remove drug source, gastric lavage, PHYSOSTIGMINE via IV reverses delerium & coma. DIAZEPAM IV used for CNS convulsions. |