Anticholinergics Flashcards
Cholinergic stimulation of muscarinic receptors by anticholinesterase produce:
Bradycardia
Hypotension
Miosis
Increased salivation
Bronchospasm
Increased peristaltic activity
Micturition/defecation
Sweating
Muscarinic effects are minimized by prior/concomitant admin of anti-cholinergics like:
Atropine-like drugs
Examples of anticholinergics/antimuscarinics include:
Atropine
Scopolamine
Glycopyrrolate
Anticholinergics/antimuscarinics block ____ receptors, but not ____ receptors
They block muscarinic cholinergic, but not nicotinic cholinergic
Anticholinergics are drugs that inhibit action of ____ on structures innervated by ______ _______ nerves
They inhibit the action of ACh, by postganglionic parasympathetic nerves
The mechanism of action of anticholinergics are:
Antagonism of ACh at the muscarinic receptors
Do anticholinergics have an effect on nicotinic receptors at the autonomic ganglia of the NMJ?
Minimal or none
The CNS has cholinergic neurons that either have ____ or ____ receptors
Nicotinic or muscarinic
Effects of atropine and scopolamine on anticholinergics are due to ____
Central anticholinergic actions
Examples of muscarinic receptor blocking compounds include:
Mandrake
Solanaceae
Jimsonweed
Deadly nightshade
With high or toxic doses, CNS effects of anticholinergics consist of: (2)
1st- stimulation
then
2nd- depression
Which class of anticholinergics cross the BBB easy?
Tertiary amines
Name the tertiary amine anticholinergics: (2)
Atropine
Scopolamine
Which class of anticholinergics does not cross the BBB easy?
Quaternary ammoniums
Name the quaternary ammonium anticholinergics: (1)
Glycopyrrolate
All anticholinergics are esters of _____ combined with an ____
Aromatic acid combined with an organic base
Glycopyrrolate does not have trophic acid since it is a quaternary ammonium. What kind of acid does it possess?
Mandelic acidd
What is the organic base of each?
Atropine
Scopolamine
Gylcopyrrolate
Tropine
Scopine
Tropine
What is the tropic acid of each?
Atropine
Scopolamine
Glycopyrrolate
Tropic acid
Tropic acid
Mandelic acid
In small doses anticholinergics affect the exocrine glands, what do they do?
Depress salivary & bronchial secretions and sweating
What is considered a small dose of atropine?
0.4-0.6
Why do atropine and scopolamine produce ocular effects?
Because they cross the BBB
Atropine and scopolamine cause: (3)
Produce mydriasis (dilated pupils)
Inhibit accommodation (for near and distant vision)
Increase IOP
Is a one-time dose of Atropine/Scopolamine safe in acute angle-closure glaucoma?
Yes
What effects do anticholinergics have on the GI and bladder system?
Decreased GI motility and secretion
Urinary retention
What effect does anticholinergics have on the respiratory system?
Drying effect
Inhibits secretions of the respiratory mucosa from the nose to the bronchi
Anticholinergics ___ airway resistance and ____ anatomic deadspace
Anticholinergics decrease airway resistance and increase anatomic deadspace
Anticholinergics produce relaxation of the bronchial smooth muscles more in ____ patients
Asthmatic/COPD
Anticholinergic stimulation is more common in
Geriatric patients
Stimulation from anticholinergics presents as:
Excitation, restlessness, or hallucinations
Depression from anticholinergics present as:
Sedation, amnesia, or unconsciousness
CNS symptoms from anticholinergics can be mitigated with an antidote… What is it and what is the dose?
Physostigmine 15 - 60 mcg/kg IV (you can repeat dose)
Large doses of atropine can cause
Convulsions
The temperature regulating center is stimulated with large doses of ____
Atropine
Atropine’s systemic effect (specifically in small doses) prevents ____ so the skin becomes ____. Which patient population is this more common in?
Prevents sweat secretion, skin becomes hot and dry. Known as “atropine fever”
More common in children
Atropine’s systemic effect (specifically in large doses) causes what?
Dilation of cutaneous blood vessels causing a red appearance known as “atropine flush”
Does atropine flush occur in small/large doses?
Large
Does atropine fever occur in small/large doses?
Small (and happens in small kids)
What are the respiratory center effects on atropine?
Slight stimulation, then depression
Increased respiratory rate
Increased MVR (rate x tidal vome)
Bronchial relaxation
Which inhalation med for COPD is a derivative of atropine?
Atrovent (ipratropium bromide)
Atropine can be dangerous in infants and small children with asthma because…
It dries the bronchial secretions and increases the risk of a mucus plug
What is the most commonly used anticholinergic to treat bradyarrhythmias?
Atropine
Out of all the anticholinergic agents, which drug increases the HR the most?
Atropine
Atropine has _____ action on the vagus nerve
Biphasic (vagus nerve is 90% parasympathomimetic)
Atropine biphasic action simply means ____
Vagal stimulation first, then vagal blockade
Bradycardia, then tachycardia
When can atropine induced bradycardia be masked?
When a large dose is given
How many mg of Atropine does it cause to produce a vagal blockade?
1mg
How many mg of Atropine does it take to produce a true or complete vagal blockade?
1-3mg
Atropine causes mydriasis (dilated pupils) by blocking the _____
Parasympathetic fiber (oculomtor or 3rd cranial nerve)
The ocular motor nerve also supplies the ciliary muscle of the lens… if atropine is given, what does this cause?
Inability to accommodate (near and farsightedness)
Which anticholinergic drug has the largest effect on the eye?
Scopolamine
In what urinary condition would you use atropine cautiously?
BPH
Large doses of Atropine decrease/increase lower esophageal sphincter pressure?
Decrease
Large doses of Atropine increase/decrease intestinal motility?
Decrease
How much of Atropine is excreted unchanged in the urine?
1/3 – 1/2
**rest undergoes hepatic metabolism
Pre-op dose of Atropine for antisialagogue/to increase HR:
0.4-0.6mg
Vagolytic dose for atropine =
0.02 - 0.03 mg/kg
The dose limit for Atropine in children is
0.6mg is MAX
Atropine dose for children > 5kg =
0.02mg/kg IV at induction or IM 30 min preop
Atropine dose for children < 5kg =
0.05-0.1mg total (not /kg)
Atropine cautions: (4)
Bladder neck obstruction
Tachycardia
Narrow angle glaucoma
Prostatic hypertrophy
Atropine does not work on a brain dead patient because ____
What med should be used instead?
Vagal activity is no longer in tact
Isoproterenol must be used (direct acting agent)
Atropine also does not work for bradycardia on a patient with a ____
Heart transplant (vagal activity is not in tact)
**Consider isoproterenol
What drug is most likely to cause CAS (Central Anticholinergic Syndrome)?
Scopolamine
What drug is used more (so also seen more with CAS)?
Atropine
CAS can cause ___ and ____
CNS stimulation and CNS depression
CNS stimulation or CNS depression?
Delirium
Hallucinations
Mania
Convulsions
Coma
Depression
CNS stimulation or CNS depression?
Dry mouth
Mydriasis (pupil dilation)
Blurred vision
Hyperpyrexia (high fever)
Restlessness
Anxiety
Stimulation
What is the antidote for CAS?
Physostigmine 15 - 60 mcg/kg
What drug class is scopolamine?
Tertiary amine
How is Scopolamine and Atropine different?
Scopolamine incorporates an O2 bridge into the organic base to form “scopine”
Which anticholinergic has less of an effect on the heart and lungs?
Scopolamine
Which anticholinergic causes greater systemic effects?
Scopolamine
Scopolamine creates good ____
Amnesia
Also depresses cerebral cortex and interrupts thought processes
Scopolamine has an advantage with children due to ____
Less tachycardia in children having heart surgery
Scopolamine eye effect in comparison to Atropine:
Stronger effect, shorter duration
Scopolamine antisialagogue in comparison to Atropine:
More powerful, shorter duration
Scopolamine’s drying effect is equal to
Glycopyrrolate
Does scopolamine cause flushing/redness?
No
*JUST atropine
Scopolamine’s metabolism:
TOTALLY metabolized by liver
When you want sedation, less increase in HR and amnesia, what drug would you choose?
Scopolamine
Scopolamine’s systemic effects include:
Sedation, amnesia and less increase in HR
Scopolamine with a ____ is best to prevent confusion & restlessness
Opioid
The max pediatric dose of Scopolamine is
0.3mg
Scopolamine patches are programmed to deliver _____ over a _____ period
1.0mg of scopolamine over a 3 day period
The total absorbed dose of Scopolamine from a patch is ____
< 0.5 mg
Glycopyrrolate is also used for:
Tongue cancer
Treatment for peptic ulcer
ECT
Children with CP (3-8 years of age)
Fiberoptic intubation/awake intubation
Glycopyrrolate produces the LEAST amount of ____
CNS and opthalmic activity
What drug class is Glycopyrrolate?
Quaternary ammonium
Glycopyrrolate & BBB
Poor penetration, no CNS effects
Is glycopyrrolate longer acting than Atropine?
Yes
Is Atropine more potent that Glycopyrrolate?
No
Normal gastric pH is
1.5 - 3
Glycopyrrolate can increase gastric ____
pH
What is glycopyrrolate’s IV onset?
1 minute (takes 20 for good drying effect to occur)
Which cholinesterase inhibitor is NOT used to reverse muscle relaxants?
Physostigmine
The degree of anticholinergic effect depends on the _____
Degree of vagal tone present in that particular patient
Atropine-like drugs block only ____
Muscarinic receptors at clinical doses
Blockade of M2 receptors in the SA node results in ____
Increased HR
Any increase in heart rate is a sign of ___
Some degree of Vagal blockade
