Muscarinic Antagonists Flashcards
Effects of M1, M3, and M5 activation?
Signal via intracellular Ca2+ increase and PKC activity
Effects of M2, M4 activation?
Signal via cAMP, decrease cAMP-dependent PK activity
Important sites of M1?
Present in CNS, sympathetic postganglionic, and presynaptic sites
Important sites of M3?
Smooth Muscle, Lungs, Eyes, Effector Cell Membranes
Important sites of M2?
Myocardium, Smooth Muscle, Presynaptic sites
slows the heart rate
Important sites of M4?
CNS
Primary clinical uses for anti-muscarinic drugs?
Ocular Exams
Incontinence
Irritable Bowel Syndrome
Use of anti-muscarinic drugs in ocular exams?
Inhibit ACh activation of M3 of pupillary constrictor–> Mydyriasis
Inhibit ACh on M3 in cilliary muscle –> Cycloplegia
What is cycloplegia
Loss of accomodation/regulation of lens thickness
Effects of anti-muscarinic drugs on incontinence?
Trigger bladder relaxation via blockage of the M3 receptor (which normally contracts the bladder), and M2 (indirectly), which would inhibit relaxation
use of anti-muscarinic drugs in treatment of IBS?
Induce GI tract intestinal paralysis
Reduce secretions
Name the anti-muscarinic drug used to treat IBS?
Mebeverine
Less popular uses for anti-muscarinic drugs?
COPD (can decrease secretions, dilate bronchioles)
Pre-Operative anti-secretor
Motion Sickness
Parkinson’s (as an adjunct to L-dopa)
What are the two types of muscarinic antagonists?
Those with a tertiary amine and those with a quaternary amine
Downside of muscarinic antagonists with a quaternary amine?
Solubility issues – only for GI or peripheral applications
Within the antagonist structure you can recognize which structure…
acetylcholine
How are tertiary amines muscarinic antagonists?
Ocular and CNS applications
Two common non-selective muscarinic antagonists?
Atropine and Scopolamine
Use of Atropine and Scopolamine?
Long duration of action
useful in treatment of GI/urinary conditions, COPD, and motion sickness
Atropine and Scopolamine. Who penetrates the CNS more?
Scopolamine
Thats why is can cause CNS side effects (ex. drowsiness)
Uses of Scopolamine specifically?
Surgical amnesia
Motion sickness patch
Problems with Scopolamine use?
Prolonged use can cause withdrawl effects upon termination of treatment
How to treat Scopolamine withdrawl?
Anti-histamines
Leave the patch on to squeeze out meds over an extended period
Indication for Tropicamide?
Cause cycloplegia and mydriasis with shorter duration than atropine. Allows for examination of the terminal ends of the optic nerve.
What are the four types of urinary incontinence?
Stress Incontinence
Urge Incontinence
Outflow Incontinence
Functional Incontinence
Important Information for Stress Incontinence?
Laxity of pelvic floor muscle
Associated with leak with cough/laugh, vaginal childbirth
Treat with adrenergic agonists
Important information for Urge Incontinence?
Increased detrusor muscle activity (Overactive bladder)
Nocturia, small volume, increased frequency
Treat with anti cholinergics
Important information about outflow incontinence?
Urinary retention secondary to obstruction or bladder atony
Nocturia, small volume, increased frequency
Treat with cholinergics (atony), alpha antagonists (obstruction)
Cause of functional incontinence
Large volume intake
Diabetic cystopathy can lead to what kind of incontinence?
Outflow incontinence
Effect of gestational diabetes on bladder fxn?
damage to bladder sphincter
leftover urine is a problem because it can lead to…
Increased urge and frequency
Effect of muscarinic antagonists on urinary incontinence?
Suppress bladder contraction
Increase maximal urine volume that causes contraction
Examples of M3 selective muscarinic antagonists in treating incontinence? Whats so cool about them?
Darifenacin and Solifenacin
Longer acting than oxybutiin
Examples of M2/M3 selective muscarinic antagonists used in urinary incontinence? Whats so cool about them?
Tolterodine
Fewer Side Effects
Example of an M1/M3 selective muscarinic antagonists used for urinary incontinence?
Oxybutynin
What is Probanthine? When do you use it?
A quaternary aminemuscarinic antagonist used in treatment of GI spasms, peptic ulcers.
Three examples of muscarinic antagonists used as anti-spasmodics.
Atropine
Dicyclomine
Hyoscyamine
Who shouldn’t be taking muscarinic antagonist anti-spasmodic drugs?
Glaucoma patients
Long term use
What drugs are used in muscarinic antagonist treatment of COPD?
IPRAtropium (short acting rescue inhaler)
TIOtropium (long acting daily inhaler)
LAMA (Long acting Musc. antagonists).
muscarinic antagonist treatments of COPD are typically paired with…
beta-adrenergic agonists
muscarinic antagonists used in treatment of Parkinsons?
Benztropine
Trihexyphenidyl
What receptor do Benztropine and Trihexyphenidyl act on?
M1 Receptor
Benztropine and Trihexyphenidyl are adjunct therapies paired with ______
L-dopa
What do Benztropine and Trihexyphenidyl do to help Parkinson’s?
Improve the balance between dopaminergic and cholinergic neurotransmission
List drug classes known to have anti-cholinergic activity
Anti-histamines
Anti-psychotics
Tricyclic Antidepressants
Anti-arrythmetics
Nortriptyline is preferred the preferred TCA for the elderly. Why?
Mild/Moderate anti-cholinergic effects
Four common contraindications for antimuscarinic drugs?
Open/Narrow Angle Glaucoma
Tachycardia
Ileus (Intestinal Obstruction)
Urinary Obstruction (causes benign prostatic hyperplasia)
