autopharm 3 Flashcards
what kind of cholinergic receptor agonists are there/ categories?
direct acting
-nicotinic
-muscarinic
indirect acting
-quaternary alcohols (short acting)
-carbamates (intermediate acting)
what receptor subtype works at neuroeffector junctions (PNS)
Muscarinic receptors
hat receptor subtype works at ganglionic synapses?
nicotinic receptors
what kind of direct-acting cholinergic agonists are there? what drugs?
-muscarinic agonists
>Bethanechol chloride (generic, Duvoid®, Urecholine®)
>Pilocarpine (generic, Isopto Carpine®)
what do muscarinic agonists do ie. what is their general mechanism of action?
- mimics ACh at neuroeffector junctions of PNS
what kind of drug is Bethanechol chloride and what are generic names?
muscarinic agonist
Bethanechol chloride (generic, Duvoid®, Urecholine®)
what does Bethanechol chloride (generic, Duvoid®, Urecholine®) do? what are its uses and effects?
- Choline ester; resistant to cholinesterases
> prolongs actions - Stimulates urinary bladder
> promotes emptying of hypocontractile bladder - Contraindicated in GI or urinary tract obstruction
> If functional increase in urethral tone; pretreat with α blocker or skeletal muscle relaxant - SLUD syndrome possible; atropine (muscarinic blocker) is antidote
what type of drug is Pilocarpine and what is its generic name?
muscarinic agonist
Pilocarpine (generic, Isopto Carpine®)
what is the use of Pilocarpine (generic, Isopto Carpine®)? what are possible complications? How does it work with Keratoconjunctivitis sicca?
Constricts the pupil (miosis) and increases aqueous outflow
* May be used to treat glaucoma
* Causes irritation to the eye resulting in compliance issues
* Newer antiglaucoma agents used more commonly
Less use now as a tear stimulant in KCS (Keratoconjunctivitis sicca)
* Relies on having some function lacrimal tissue
* Largely replaced by cyclosporine for immune mediated KCS
* Can be used in neurogenic KCS where lack of neurogenic
input to lacrimal glands is the problem; directly stimulate muscarinic receptors on the gland to produce tears
what are the characteristics of indirect-acting cholinomimetic drugs? how do they work, generally, and what are the resulting effects? what is the mechanism?
- Anticholinesterase drugs ie. inhibitors of ACh metabolism
- Resultant effects similar to direct-acting cholinomimetics
- Normally ACh is rapidly degraded in synapse by acetylcholinesterase
> Very short half-life (T1/2= 40 μsec) - Anticholinesterase drugs block acetylcholinesterase > increase ACh in synapse
=>Muscarinic or nicotinic receptor stimulation can result
what type of drug is edrophonium? what is its generic name?
Indirect-acting cholinomimetic drugs
-Quaternary alcohol
* Edrophonium (generic, Tensilon®)
what is the mechanism of action for edrophonium? how does it work and what does it do? whata re notable characteristics?
- Bind reversibly to active site of cholinesterase
- Prevents access of cholinesterase to ACh > increase Ach levels in synapse
- Short duration of action (T1/2 of 2-10 min)
- Poor penetration into CNS due to charged polar molecule
- Available in injectable formulation
what type of drugs are Neostigmine and Pyridostigmine? what are their generic names?
Neostigmine (generic, Prostigmin®), Pyridostigmine (Mestinon®)
indirect-acting cholinomimetic drugs
>carbamate esters
what are Neostigmine (generic, Prostigmin®) and Pyridostigmine (Mestinon®)? how do they work and what do they do? what are some notable characteristics?
- Carbamylates active site of cholinesterase
- Carbamylated enzyme more resistant to hydration step
- Longer duration of action (T1/2=30-60 min)
- Poor CNS penetration
- Available in oral and injectable formulations
therapeutic uses for Neostigmine, Pyridostigmine
at neuromuscular junction, helps with Myasthenia gravis