Muscarinic Agonists Flashcards
Describe the mechanism of diabetic autonomic neuropathy
metabolic insult to nerve fibers, neurovascular insufficiency, autoimmune damage, neurohomormonal growth factor deficiency
Significance of cardiovascular autonomic neuropathy?
increased risk of silent myocardial ischemia/mortality
Autonomic, mainly vagal, nerve dysfunction is common in which types of patients and it’s exaggerated by what?
common in patients with liver diseases and is further exaggerated by alcohol abuse
Advanced chronic liver disease is characterized by?
peripheral arterial vasodilation and increased plasma catecholamine concentrations
Botulism toxin poisoning can occur through?
contamination with the toxin (Clostridium botulinum), through an open wound (more commonly observed with i.v. drug users), or with bad botox injections
Symptoms of botulism toxin poisoning?
weakness, trouble seeing, feeling tired, and trouble speaking (similar to myasthenia gravis)
How does Botulism toxin work?
interacts with SNARE proteins preventing vesicle Ach neurotransmitter release
What is Graves’ disease?
autoimmune disease where a thyroid-stimulating immunoglobulin acts like TSH and stimulates the secretion of T4 and T3
Symptoms of Graves’ disease?
mimics a hyperadrenergic state - feeling hot, excessive sweating, irregular heartbeat/tachycardia, diarrhea/hyperdefecation, dry eyes, weight loss, hypertension
How do you treat Graves’ disease?
treatment with beta-blockers
muscarinic agonists are contraindicated
Glucocorticoids released by the adrenal gland inhibit the formation of what?
the enzyme that converts T4 -> T3
Hashimoto’s disease
autoimmune disease where antibodies attack the thyroid
Symptoms of hypothyroidism
cold, dry skin, constipation, slowed heart rate, weight increase, hair loss
Why is clinical use of muscarine not recommended?
it can cross the BBB and cause convulsions
Methacholine
used to diagnose bronchial hyperreactivity (asthma, COPD) because of its short duration of action
What happens when you give methacholine to a patient with bronchiol hyperreactivity?
people suffering from bronchial hyperreactivity will show signs of respiratory insufficiency at a lower dose than healthy individuals
What causes glaucoma?
build up of aqueous humor in the iris either due to a decrease in drainage and/or increase in aqueous humor production
Open angle glaucoma
clogged or obstructed canal or schlemm, slowly progressing disease typically not apparent until nerve damage of the eye occurs
Narrow angle or closed angle glaucoma
drainage blocked by the iris muscles, more acute and severe, can quickly lead to blindness if left untreated
treatment of open angle glaucoma
can be treated using M3 muscarinic agonists which will help stretch the trabecular meshwork and reduce clogging
M3 treatment of open angle glaucoma relies on what?
muscarinic agonist ability to contract the sphincter muscles
Muscarinic agonists used for the treatment of glaucoma
carbachol and pilocarpine
Pilocarpine
partial agonist, relieves block of canal of Schlemm, may have less side effects like headache than carbachol
Adverse effects of pilocarpine
sweating ,salivation, diarrhea, bronchial mucus secretion, bronchospasms, bradycardia, vasodilation, miosis, impaired night vision, can cross the BBB and cause seizures
Bethanechol
used for urinary retention problems and post-operative ileus, orally active (not metabolized quickly), muscarinic selective
Cevimeline and pilocarpine
used to treat dry mouth, which is a symptom of Sjogren’s syndrome or a side effect of radiation treatment
most well known nicotinic receptor agonist
exogenous nicotine
Nicotine as a patch is used for?
smoking cessation
Contraindications for nicotine as a drug
cardiovascular issues
Varenicline (Chantix)
alpha4beta2 nicotinic receptor partial agonist, activates nicotinic receptor much less than nicotine; blocks nicotine from binding
What kind of drugs can reduce intraocular pressure by decreasing formation of aqueous humor rather than by changing the size of the pupil?
Timolol (beta blockers)
