Cholinergic Receptor Activating Drugs Flashcards
What are the two classes of cholinoceptor stimulant drugs?
Direct acting and nondirect acting
Which type of cholinoceptor shows virtually no selectivity with cholinoceptor agonists?
muscarinic; they do have some selectivity with muscarinic antagonists though
Which enzyme do the indirect-acting cholinoceptor stimulants inhibit?
acetylcholinesterase-amplifies endogenous Ach
Name the 4 direct acting muscarininc cholinomimetics and distinguish which is a carbamic acid ester
Bethanecol (Carbamic acid ester); Muscarine, Pilocarpine, and Cevimeline (non-ester alkaloids)
What is Bethanecol used to treat?
Post-operative and neurogenic ileus (bowel obstruction) ; urinary retention
What is Pilocarpine used to treat?
Glaucoma; it causes contraction of the ciliary body to reduce intraocular pressure
What is the mechanism of action of the direct acting cholinoceptor activators?
they bind to and directly activate muscarinic or nicotinic receptors
What chemical change from carbacol to bethanechol allows the drug to be resistant to hydrolysis?
substitution of a carbamic acid group
What is Cevimeline used to treat?
Dry mouth (ex: Sjogren’s, post-radiation therapy) increases salivation
Name 1 direct acting nicotinic cholinomimetic and state whether it is a non ester alkaloid or a carbamic acid ester.
Nicotine; non ester alkaloid
What is nicotine used for?
smoking cessation; reduces cravings
What are the common side effects of all direct acting muscarinic cholinomimetics and what drug can they be blocked by?
Salivation Lacrimation Urination Defecation GI distress Emesis -blocked by atropine
Name the 5 indirect acting cholinoceptor activating drugs. Oh yeah and what enzyme do they inhibit again?
Neostigmine, physostigmine, Donepezil, Edrophonium and Echothiphate; acetylcholinesterase
Which of the indirect acting cholinoceptor activators is hydrophobic and crosses the BBB and which disease is it therefor used to treat?
Donepezil; Alzheimers Disease
What is neostigmine used to treat and is it short or long acting?
Post-operative and neurogenic ileus (bowel obstruction), urinary retention, myasthenia gravis, reversal of neuromuscular blockade; short acting (0.5-2 hours)
What is Physostigmine used to treat and is it short or long acting?
Glaucoma- it causes contraction of the ciliary body and papillary sphincter to reduce intraocular pressure; short acting (0.5-2 hours)
What is edrophonium used to treat and is it short or long acting?
Myasthenia gravis (differentiating deficiency versus ACh crisis); ileus (bowel obstruction); very short acting (5-15minutes)
What is echothiophate used to treat and is it short or long acting?
Glaucoma-it causes contraction of the ciliary body and papillary sphincter to reduce intraocular pressure; Long acting (>100 hours)
What is the mechanism of action of Pralidoxime?
regenerates phosphorylated actylcholinesterase (its a strong nucleophile)
What is pralidoxime used to treat?
poisioning by nerve gas or insecticides
What are the common side effects of all the indirect acting cholinoceptor activating drugs?
SLUDGE, general increase in cholinergic neurotransmission and paralysis
Which two drugs should be included in the therapy for toxicity from cholinesterase inhibitors as in insecticides and nerve gas?
atropine and pralidoxime
Which 3 drugs can be used to treat glaucoma?
pilocarpine, echothiophate and physostigmine
Which 2 drugs can be used to treat bowel obstruction (ileus) and urinary retention?
Bethanecol and Neostigmine
Which 2 drugs can be used to treat myasthenia gravis?
neostigmine and edrophonium
What are the effects of cholinoceptor activating drugs on the eyes?
contraction of the sphincter muscle of the iris and the ciliary muscle
What are the effects of cholinoceptor activating drugs on the Heart?
decrease-rate, contractile force in atria and ventricles, conduction velocity
increase-refractory period
What are the effects of cholinoceptor activating drugs on the blood vessels?
Dilation through EDRF (NO), or constriction at high doses
What are the effects of cholinoceptor activating drugs on the GI tract?
increase motility, relax sphincters and stimulate secretion
What are the effects of cholinoceptor activating drugs on the bladder?
contract detrusor, relax sphincter and trigone
What are the effects of cholinoceptor activating drugs on the glands?
secretion
