Flashcards in Ch.11: Anticholinesterase Drugs Deck (31):
drugs that inhibit the enzyme AChE, which degrades Ach. Result is to intensify Ach actions via INDIRECT activation of cholinergic receptors
are anti-cholinesterase agents agonists or antagonists?
NEITHER. They indirectly activate cholinergic receptors
Butyrlcholinesterase (BuChe) fx
(not on list)
hydrolyzes Ach and other esters
unknown physiological role
inhibited by most AChE inhibitors
What happens to BP after administration of AChE inhibitor?
classification of Anti-cholinesterase agents is based on:*
the duration of enzyme inhibitioin by the inhibitor, which is related to the speed with which inhibitor dissociates from the esteratic site of AChE. Chemical structure determines all of this.
rank 3 types of anti-cholinesterase agents in order of shortest to longest acting
quaternary < carbamates < organophosphates
therapeutic uses of reversible anti-AChE agents
-Diagnostic for myasthenia Gravis
How does edrophonium work?
blocks Ach breakdown at neuromuscular jx and promotes Ach stimulation of nicotiic receptors on skeletal muscle. Is a short acting agent
contraindications for use of Anti-AChe agents
-ill or debilitated
-GI/urinary tract obstruction
-recent exp. to anti-AChE agents
-food or dairy animals
-very young or old
Is edrophonium hydrolyzed by AChE?
How is edrophonium eliminated?
renal excretion (rapid)
therapeutic uses of edrophonium
-temporary reversal of competitive muscle relaxants
-differential diagnosis of myasthenia gravis
Therapeutic uses of neostigmine
-treat myasthenia gravis
-ruminal or GI stimulant
-reversal agent for muscle relaxants
(anti-parasitic, pupillary constriction)
duration of action of neostigmine
intermediate (1-3 hrs)
does neostigmine cross BBB?
class of neostigmine
How is neostigmine eliminated?
hydrolyzed by AChE and pseudo-ChE
class of physostigmine
therapeutic uses of physostigmine
similar to neostigmine, but exhibits greater CNS activity
Drugs potentiated by anti-AChE agents**
Drugs antagonized by anti-AChE agents**
drug that antagonizes Anti-AChE agent
OP-Type acetylcholinesterase inhibitors are used in what setting?
agriculture for pest/rodent control, as nerve gas. Not used clinically
metabolized in liver to active form (paraxon)
How do OP agents work?
form covalent bond with AChE to inhibit it. Becomes irreversible
What class is parathion?
irreversible anticholinesterase (OP-type inhibitor)
most common uses of parathion***
agricultural insecticide, urban mosquito control, cattle dip or spray
How can you recover from OP-type AChE inhibitors?
only way to recover is to make new enzyme (takes a long time!)
Signs of acute OP poisoning
inhaled: ocular, respiratory
oral: GI, systemic, SLUD*
cutaneous: sweating, muscle fasciculations, systemic signs
SLUD is assoc. with overstimulation of:
parasympathetic transmission in the body