Anticholinergics Flashcards
Cholinergic receptors are broadly divided into _______ and ______ receptors
Nicotinic
Muscarinic
Where are Nn receptors present❓
Ganglia
Adrenal medulla
Nn blockers are referred to as ganglion blockers
Where are Nm receptors found❓
Neuromuscular junctions
Nm antagonists are therefore referred to as neuromuscular blockers
Where are M1 receptors found❓
Gastric ganglia
CNS
Where are M2 receptors found❓
Heart
CNS
Where are M3 receptors found❓
Eye GI Bladder Bronchus Glands CNS
M3 and M4 receptors are found in the CNS
True or false
True
How are antimuscarinics classified❓
Natural alkaloids
Semisynthetic derivatives
Synthetic compounds
Give a few examples of antimuscarinic natural alkaloids
Atropine
Hyosine/Scopalamine
Atropine is…
- Rapidly absorbed from❓
- Distributed❓
- Metabolized in the❓
- Half life❓
- Upper small intestine
- Throughout the body
Crosses BBB
Crosses placenta - Liver, 50%, by hydrolysis
3-4hrs
Hycosine is more metabolized and has a better BBB penetration than atropine
True or false
True
List the antimuscarinic spasmolytics you know
Atropine
Hyosine butyl bromide/Buscolysin®️
Oxyphenonium (GI)
What is the mechanism of action of antimuscarinics❓
🚫Action of Ach on autonomic receptors innervated by parasympathetic postganglionic neurons
Atropine stimulates the CNS but higher doses are required than for peripheral nerve stimulation
True or false
Why❓
True
Some level of restriction to BBB crossing
Highlight the effects of atropine
CNS stimulation
🚫Cholinergic overactivity in basal ganglia
⬇️tremor and rigidity in parkinsonism
What drugs would you combine in the treatment of Parkinsonism❓
Why❓
Antimuscarinic+Dopamine precursor drug
May provide more effective therapy than either drug alone
List a few examples of antimuscarinic semisynthetic derivatives
Homatropine
Hyoscine butyl bromide/Buscolysin®️
List a few examples of antimuscarinic synthetic compounds
Oxyphenonium
Pirenzepine
Ipratropium, Tiotropium
Flavoxate, Oxybutynynine, trospium
Tropicamide
Benztropine, Biperiden, Trihexyphenidyl
Which antimuscarinic semisynthetic derivative is a…
- Mydriatic
- Spasmolytic ❓
- Homatropine
2. Hyosine butyl bromide/Buscolysin®️
Which antimuscarinic natural alkaloid is a…
- Mydriatic
- Spasmolytic
- Antiemetic ❓
What is it’s significance❓
- Atropine
- Atropine
- Hyosine
It can be used to treat nausea/vomiting/motion sickness
Which antimuscarinic synthetic compound is a…
- Mydriatic
- Spasmolytic
- Antiulcer
- Antiasthmatic
- Antidysuric
- Antiparkinsonian
- Tropicamide
- Oxyphenonium (GI spasmolytic)
- Pirenzepine
- Ipratropium, Tiotropium
- Flavoxate, Oxybutynynine, trospium
- Benztropine, Biperiden, Trihexyphenidyl
List the antimuscarinic mydriatic you know
Atropine
Homatropine
Tropicamide
Which antimuscarinic would you use to treat a patient with dysuria❓
Flavoxate
Oxybutynynine
Trospium
Which antimuscarinic would you use to treat a patient with Parkinsonism❓
Benztropine
Biperiden
Trihexyphenidyl
There are drugs that aren’t antimuscarinics with antimuscarinic properties.
Do you know any❓
Antihistamines
Tricyclic antidepressants
What effects will pharmacological doses of atropine cause❓
What effects will high doses of atropine cause❓
✅
CNS excitation
⬆️
Restlessness
Hallucinations
Delirium
Respiratory depression
Coma
What effects will pharmacological doses of hyoscine cause❓
What effects will high doses of hyoscine cause❓
✅ CNS depression: Drowsiness Amnesia Fatigue Dreamless sleep
⬆️ CNS excitation: Restlessness Hallucinations Delirium
Used in preventing motion sickness
“Twilight sleep” is induced by ______
What is it’s application❓
Hyoscine
Truth serum for crime suspects
How would you apply the antiemetic properties of hyosine❓
Used to preventing motion sickness: transdermal patch placed behind pinna
What are the effects of anticholinergic drugs on the eye❓
Mydriasis (relaxation of cilliary muscle)
Photophobia
Cycloplegia
⬆️Intraocular tension
⬇️Lacrimal secretion (dry/sandy eyes)
How do antimuscarinics cause cycloplegia?
Paralysis of cilliary eye muscles ⬇️ 🚫of accommodation ⬇️ Focused for far vision
Which antimuscarinic would you use to treat iritis, choroiditis, keratitis and corneal ulcers❓
Why❓
Atropine
It has a long lasting mydriatic-cycloplegic and local anodyne action on the cornea
Antimuscarinics should be carefully administered in patients with glaucoma.
Why❓
Why is this significant❓
- Antimuscarinics
⬇️
Relaxation of ciliary muscle
⬇️
Obstruction of drainage of aqueous humor
⬇️
⬆️IOP
- Contraindication in pts with narrow arrow angle glaucoma b/c of likelihood of complete obstruction of flow of aqueous humor
Refer to photos*
OR
http://tmedweb.tulane.edu/pharmwiki/doku.php/antimuscarinics