Cholinergics:Acetylcholinesterase inhibitors Flashcards
agents that enhance the effects of endogenously released acetylcholine by blocking its natural breakdown by the enzyme acetylcholinesterase
Acetycholinesterase inhibitors
Sites of action of acetylcholinesterase activity
Post-ganglionic parasympathetic neuroeffector junctions
- Sympathetic and parasympathetic ganglia
- Skeletal neuromuscular junction
- CNS (if penetrate into the CNS)
Sites of action of acetylcholinesterase activity
is it sympathetic, parasympathetic or neither or both
ganglia
both
Sites of action of acetylcholinesterase activity: is it in CNS?
if it can penetrate the CNS but must be lipophilic
During breakdown of Ach, Ach is temporarily _____ and then acetate is removed via:
acetylated
removed via hydrolysis
Edrophonium is
Non-substrate reversible AchE inhibitors
Edrophonium acts by:
reversibly, competitive inhibitors for the substrate binding domain
Edrophonium is truly reversible competitive enZ inhibitor and non-covalent or covalent binding
covalent
Onset of Edrophonium is delayed/rapid onset
rapid onset
Duration of action of Edrophonium
and short duration of action (minutes)
Administration route of Edrophonium
- not orally active; i.v. administration
Uses of Physostigmine
1) treatment of chronic wide angle glaucoma (ophthalmic application)
2) toxicity by antimuscarinic drug poisoning (i.v.; penetrates into the CNS and can treat CNS toxicity by these agents)
Physostigmine is slowly/rapidly reversible
slowly
Physostigmine is a tertiary amine (lipophilic) which can penetrate cell membranes and thus can have
CNS effects
Neostigmine: type of drug
“Reversible” substrate inhibitors of acetylcholinesterase
Neostigmine is rapidly/slowly reversible
slowly
Neostigmine has no CNS affects because
it’s a quarternary amines thus positively charged
treatment of myasthenia gravis
Neostigmine
prevention and treatment of post-operative atony of gut and bladder (oral)
Neostigmine
Delivery of neostigmine for prevention and treatment of post-operative atony of gut and bladder
(oral)
reversal of paralysis by competitive neuromuscular blocking drugs (i.v.)
Neostigmine
reversal of paralysis by competitive neuromuscular blocking drugs by Neostigmine; delivery method:
IV
During breakdown of Ach, the Ach is temporararily
__________ and then _______ is removed by hyrdolysis
acetylated
acetate
process of Ach breakdown is
rapid
Non-substrate reversible AchE inhibitors
Edrophonium
Can edrophonium enter CNS?
why or why not?
nope
has charged amine
Two types of reversibe AcheE substrate inhibitors
Neostigmine
Physostigmine
Difference of delievery between neostigmine and physostigmine?
Neostigmine is quartanary amine so no CNS penetration
Drug promotes signaling at neuromuscluar jnx and prevents muscle weakness that you get form Myasthia Gravis
Neostigmine–given orally
Reversible Acetylcholinesterase used to treat wide eyed glaucoma
Physostigmine
If you are suffering from toxicity by antimuscarinic drug poisoning (penetrates into the CNS and can tx CNS toxicity)
Physostigmine
Neostigmine works by nesting in the AchE and get degraded so it slowly breaks down: how does this affect muscle contraction?
Ach stays in post cleft longer thus greater muscle contraction.
Side affects of reversible AchE inhibitors
SLUDGE, hypotension, bradycardia, blurred vision
What does SLUDGE stand for
salivation lacrimation urination defication GI issues emisis = vomitting
Why do we get blurred vision from reversible AchE inhibitors?
bc we are promoting PNS activity in cliliary msl so get lots of contraction of ciliary msl
Used to diagnose myasthenia gravis
used to treat myastenia gravis
edrophonium
neostigmine
used to distinguish cholinergic from mysthenic crisis
edrophonium
Drug used to reverse paralysis by competitive neuromuscular blocking agents
edrophonium