Anticholinergic Agents/Muscarinic Antagonists Flashcards
What is the MOA of anticholinergics/muscarinic antagonists?
competitive inhibitors of ACh at parasympathetic muscarinic receptors to increase HR
What effects do anticholinergics/muscarinic antagonists have on the body?
- increased HR
- salivary inhibition
- decreased bronchial and GI secretions
- decreased gastric motility
- bronchodilation
What are muscarinic antagonists/anticholinergics used for?
to antagonize the muscarinic effects of anticholinesterases used to reverse NMBA
Atropine Dosing
- 0.014 mg per 1mg of edrophonium
- 0.2 - 0.4 mg for vagal stimulation
Atropine onset and duration
Onset: < 1 min
Duration: up to 30 min
Is atropine a quaternary or tertiary amine? Can it cross the BBB?
- tertiary amine
- it CAN cross the BBB
When is atropine used?
- reversal with edrophonium
- brady arrythmias
- vagal stimulation
- oculocardia reflex
- peritoneal stimulation
What is the effect of atropine in the fetus?
crosses the placenta and increases FHR, decreasing beat to beat variability
We should very carefully use atropine in patients with ___________
narrow-angle glaucoma
Glycopyrrolate Dosing
0.2 mg per 1mg of neostigmine
Glycopyrrolate onset and duration
Onset: 1 min IV; 15-30 min IM
Duration: 2-4 hours
What is the MOA of glycopyrrolate?
- synthetic antimuscarinic
- competitive ACh antagonist
When is glycopyrrolate used?
- reversal with neostigmine
- antisialogogue (xerostomia)
- to increase HR (not as intense as atropine)
Is glycopyrrolate a quaternary or tertiary ammonium? Can it cross the BBB?
- quaternary ammonium
- CANNOT cross the BBB
What two side effects are not seen in glycopyrrolate that would normally be seen in other muscarinic antagonists?
- no CNS effects
- no mydriasis
Scopalamine Dosing
0.3 - 0.5 mg IV or IM
What is the MOA of scopalamine?
- competitive antagonist of ACh at muscarinic receptors
- antagonizes histamine and serotonin
Is scopalamine a quaternary or tertiary amine? Can it cross the BBB?
- tertiary amine (naturally occurring alkaloid)
- it CAN cross the BBB
When is scopalamine used?
- to decrease secretions
- decrease PONV
- motion sickness/vertigo
- dilate pupils/cycloplegia
- unstable trauma patient
- sedation/amnesia
What is the effect of scopalamine in elderly?
can cause toxic psychosis
T/F: It is safe to use scopalamine in elderly
false
- can cause toxic psychosis
What is an important thing to do after you administer or place a scopalamine patch?
wash your hands!!!!
can easily cause your eyes to dilate
What are common CNS effects of scopalamine?
- restlessness
- agitation
What routes of administration are available for scopalamine?
- IM
- IV
- transdermal patch
If a patient is prescribed a trasdermal patch for scopalamine, what should we warn them about?
- very blurry vision
- vertigo
- dizziness
- risk of falling
Can we overdose on muscarinic antagonists?
yes - leads to anticholinergic syndrome
What can be a cause of anticholinergic syndrome?
overdose of atropine, scopalamine, or phenothiazine
What are s/s of anticholinergic syndrome?
- anxiety
- disorientation
- hyperactive (mad hatter)
- sedation
- seizure
- mydriasis (blind as a bat)
- increased HR
- atropine flush (red as a beet)
- dry/flushed skin and mucous membranes (dry as a bone)
- atropine fever (hot as a hare)
