Drugs Mimicking Pan Flashcards
How can their action be induced
Directly activating muscarinic receptors
Indirectly activating muscarinic receptors through inhibition of cholinesterase enzyme
What are the direct muscarinic agonists
▪️Choline esters like bethanechol which is similar to ach and resistant to hydrolysis
▪️Cholinomimetic alkaloids like pilocarpine
Tertiary amine well absorbed from GIT and enters CNS easily
Therapeutic uses of muscarinic receptor agonists
Postoperative paralytic ileus (bethanechol)
Pilocarpine to inc salivary secretion in treatment of xerostomia in sjögren syndrome
What do anticholinestrases do
Inhibit action of both true and pseudocholinesterase enzymes
Can prolong and potentiate action of ach at:
Muscarinic receptors in PNS
Nicotinic receptors at NMJ
Nicotinic and muscarinic receptors in CNS to improve cognitive functions
Reversible anticholinestrases
Neostigmine
Irreversible anticholinestrases
Organophosphorus compounds
Therapeutic uses of anticholinestrases
Myasthenia gravis: poor penetration: neostigmine
Pyridostigmine: longer half life
Atropine: intolerable adverse effects
Edrophonium: short half life and used for diagnosis
▪️Neostigmine can also be used to reverse effects dir to excess competitive neuromuscular blocking agents at end of surgical anesthesia
▪️paralytic ileus and postoperative urine retention: Neostigmine and pyridostigmine
▪️Alzheimer’s disease: donepezil
Signs of opcs toxicity
Severe manifestations of muscarinic receptor activation (secretions)
Cns manifestations in form of confusion, convulsion and coma
Muscle fasciculations, weakness and paralysis
What are the non specific measures to manage opc toxicity
Termination of further exposure
Maintain parent airway
Supportive measures
Control of convulsions by diazepam
Specific antidotes for opc toxicity
Atropine competes with ach at muscarinic receptor
Oximes to reactivate cholinesterase
Should be give as early as possible
Up to 6 hours
