Autonomic Drugs: Acetylcholine B&B Flashcards
name 5 places where acetylcholine receptors are found in the body
- muscarinic parasympathetic receptors in cardiac and smooth muscle, glands
- muscarinic sympathetic receptors in sweat glands
- nicotinic somatic receptors in skeletal muscle
- nicotinic receptors in 1st synapse of SNS and PNS
- nicotinic receptors at adrenal medulla
explain why flushing occurs with muscarinic antagonists
muscarinic receptors are found in parasympathetic system + SWEAT GLANDS of SNS
block muscarinic receptors —> no sweat —> increased body temp —> skin flushing
how do muscarinic agonists affect endothelial cells?
no direct effect on vascular smooth muscle
indirectly stimulate NO release —> activates guanylate cyclase —> less intracellular calcium —> vasodilation and lowered BP
what is the clinical use of the following acetylcholine agonists?
a. bethanechol
b. carbachol
c. pilocarpine
d. methacholine
a. Bethanechol: activates Bowel and Bladder to treat urinary retention
b. carbachol: lowers intraocular pressure to treat glaucoma or pupillary constriction
c. pilocarpine: lowers intraocular pressure to treat glaucoma
d. methacholine: bronchoconstrictor used to diagnosis asthma
name 2 acetylcholine agonists which lower intraocular pressure to treat glaucoma
- carbachol
- pilocarpine
what kind of drug is bethanechol?
Bethanechol: acetylcholine agonist, activates Bowel and Bladder to treat urinary retention (ex, after surgery)
what kind of drug are carbachol and pilocarpine?
acetylcholine agonists
carbachol: lowers intraocular pressure to treat glaucoma or pupillary constriction
pilocarpine: lowers intraocular pressure to treat glaucoma + treats Sjögren’s syndrome (increases salivation)
what kind of drug is neostigmine, and for what is it used?
acetylcholine esterase inhibitor (non-competitive, covalent but reversible) —> increases activity of ACh
used to treat urinary retention and myasthenia gravis
what kind of drugs are pyridostigmine and edrophonium, and what do they treat?
acetylcholine esterase inhibitor —> increases activity of ACh
edrophonium (competitive, reversible) - used for diagnosis of myasthenia gravis
pyridostigmine (non-competitive, covalent but reversible) - used to treat myasthenia gravis
what is physostigmine used for?
acetylcholine esterase inhibitor (non-competitive, covalent but reversible) —> increases activity of ACh
used to treat anti-cholinergic toxicity (such as by atropine) and glaucoma
a pt in the ED is accidentally given an overdose of atropine - what should you prescribe to reverse the effects?
atropine = anti-cholinergic drug
give physostigmine (ACh esterase inhibitor) to reverse the toxicity
what kind of drug is donepezil, and what does it treat?
acetylcholine esterase inhibitor —> increases activity of ACh
used to treat Alzheimer’s (in which there is decreased ACh activity)
what is the clinical use of the following acetylcholine esterase inhibitors?
a. neostigmine
b. pyridostigmine
c. edrophonium
d. physostigmine
e. donepezil
a. neostigmine - urinary retention, myasthenia gravis
b. pyridostigmine - myasthenia gravis (tx)
c. edrophonium - myasthenia gravis (dx)
d. physostigmine - anti-cholinergic toxicity (ex, atropine), glaucoma
e. donepezil - Alzheimer’s
which receptors are affected by myasthenia gravis? how does it present?
autoantibodies against ACh receptors, primarily nicotinic receptors in skeletal muscle
—> presents with problems of eye/chewing/talking/swallowing
—> classic finding is fatiguability due to decreasing ACh levels with more movement
COPD and peptic ulcers are similar in that they can both be worsened by what type of medication? explain
cholinergic (ACh agonist or ACh-esterase inhibitor) medication
bronchoconstriction —> COPD flare
increased gastric acid —> ulcers