Chapter 16-17 Muscuranic Agonists and Antagonists (r/t bladder) Flashcards
(17 cards)
What is overactive bladder (OAB)?
AKA urinary urgency incontinence or detrusor instability
Seen more in 75+
First line tx is behavioral modification then pharmacology
What is the medication of choice for OAB? Why?
Anticholinergics are the class of choice.
Parasympathetic NS controls bladder contractions; thus by blocking muscarinic receptors bladder activity decreases.
What is important when considering a medication for a comorbidity?
Specificity!
The more SPECIFIC the less likely there are side effects (more protein bound)
What medication is highly selective and very expensive? Which receptor is acted upon?
Darifenacin (Enablex®)– Highly M3 selective (muscarinic antagonist)
Minimal a/e
What do receptor antagonists do against parasympathetic sites for OAB?
Inhibit cortexin (CTXN) a protein involved in neuronal signaling
What medication is primarily selective and less expensive? What receptor is acted upon?
Oxybutynin (Ditropan®; Oxytrol®), Solifenacin (VESIcare®)
Memory aid: VESIcare helps you always have dry underwear
Primarily M3 Selective (muscarinic antagonist)
What medication is not selective and inexpensive?
Festerodine (Toviaz®)
Tolterodine (Detrol®; Detrol LA®), Trospium (Sanctura®; Sanctura XR®)
(muscarinic antagonist)
GREATER a/e d/t poor selectivity
Sympathetic drugs do what for OAB? Example?
Cause bladder relaxation by increasing storage
Beta 3 Adrenergic agonists
Mirabegron (Myrbetriq®), Vibegron (Gemtesa®)
When would a/e occur for anticholinergic medications? Common a/e? Use cautiously with?
Typically dose related: URINARY RETENTION is a big one
Caution with antihistamines, tricyclic antidepressants, phenothiazine antipsychotics
Muscarinic Agonist do what for Urinary Retention?
Activate muscarinic receptors of the urinary tract by relaxing trigone and sphincter muscles, increasing voiding pressure by contracting the dettrusor mm., and useful in postop/PP pt urinary retention
A/e of muscarinic agonists? SLUDGE & KILLER Bs!
Salivation
Lacrimation
Urination
Defication
GI issues
Emesis
Bronchospasm, Bronchorreha, Burred vision, Bradycardia, shock
Urinary Retention tx?
Bethanechol (Urecholine)
- Direct-acting muscarinic AGONIST
Uses
Urinary retention
Adynamic ileus -> causes increased intestinal motility
Gastric atony -> cause
Contraindicated in patients with:
Peptic ulcer disease, urinary tract obstruction, intestinal obstructions,
hypotension, asthma, coronary insufficiency, and hyperthyroidism
Administer
1 hour before or 2 hours after meals
Where are muscarinic receptors located?
Sweat glands, blood vessels, all organs regualted by the PSNS
What general affects do muscarinic receptors impose?
Decrease HR, increase gland secretion, smooth mm. contraction
What are the muscarinic subtypes? M1, M2, M3 allocated to?
M1 - Salivary & CNS
M2 - Heart
M3 - Bladder detrusor
What is the response to M3 activation? Inactivation?
Activation - contraction (increase pressure)
Blockade - Relaxation (decreased pressure)
Which medication should you consider for safety regarding a patients hx of glaucoma?
miragebron
urecholine
tolterodine
solifenacin
Mirabegron d/t its effect as a beta 3 adrenergic agonist, NOT as an anticholinergic medication!
THINK SLUDGE & KILLER Bs!
