Cholinergics - Muscarinic Receptor Agonists Flashcards
What are general effects of muscarinic receptor agonists?
produce general parasympathetic effects
Are muscarinic drugs generally selective?
No -> muscarinic receptors all over and very little selectivity
What is the significance of muscarinic receptors on endothelial cells?
Even though blood vessels not controlled by parasympathetic system, still contain receptors, so can have effect on vascular tone
What are the uses and route of administration of Bethanechol?
subQ injection to promote urination in case of post op retention, retention b/c diabetic neuropathy, bladder disorders
can also administer orally to promote GI movement
What is the significance in the quaternary amine structure of bethanechol?
always (+) charged so cannot enter CNS
Can you administer bethanechol IV? Why/Why Not?
No b/c will cause hypotension due to muscarinic receptors on endotheliel cells
What are the main organ systems affected by muscarinic agonists?
Eye -> contraction of ciliary muscle to focus lens for near vision, also cause miosis
Heart -> decrease conduction b/c receptors on SA/AV nodes
Lung - constriciton of bronchi, promotion of secretions
Bladder -> promote urination
GI tract -> salivation, increased gastric secretions, increased intestinal tone and motility
Sweat glands -> sweating
Blood Vessels -> vasodilation
What are the general side effects of muscarinic agonists?
SLUDGE
S - Salivation, L - lacrimation, U - urination, D - defication, G - gastrointestinal upset, E - emesis (vomiting)
Also, hypotension, bradycardia, difficulty with visual accomodation
What conditions should muscarinic agonists be used in caution with?
COPD + Asthma (b/c bronchoconstriction)
Urinary or GI obstruction
Peptic ulcer
CV disease -> bradycardia, hypotension, hyperthyroidism
What is the main use of pilocarpine?
Orally to treat xerostomia (dry mouth)
Opthalmic - treat wide angle glaucoma and emergency treatment for narrow angle glaucoma
What is the significance of the structure of pilocarpine?
lipophillic -> can penetrate CNS
What blocks the side effects of systemic exposure from Bethanechol and Pilocarpine?
Atropine
