Cholinoceptor Activating & Cholinesterase inhibiting Drugs Flashcards
what are the 2 main cholinergic receptors?
Nicotinic (Nm, Nn) and muscarinic (M1, M2, M3)
fill in the red spaces or say where do we find these receptors?
Fill in the red spaces or mention what effect will the receptor have in the target organ
Also remember that M2 will have decreased AV conduction
Acetylcholine or drugs acting like acetylcholine produces following effects in body:
- Heart
- blood vessels
- smooth muscle of lungs
- smooth muscle of ballder
- spincters of the GI and bladder
- pupils
- glands
- Heart : Reduces HR (Bradycardia),FOC, CO and BP
- Blood vessel: Vasodilatation and lowers BP
- Smooth muscle contraction in GIT, bronchus, and bladder: Thus there will be Diarrhea, Bronchoconstriction and Urination
- Sphincters in GIT and bladder: Relaxation
- Pupil: Miosis and ciliary muscle contraction
- Glands : more Salivation, sweating, gastric acid secretion , tracheobronchial secretion, lacrimation and urination
ACh carrying nerves are called as what?
cholinergic fibers
cholinergic fibers are present in what divisions of the nervous system?
somatic and ANS
what is a cholinergic agonist?
what are the 2 types of cholinergic agonist? define them
Drugs which mimic or increases the actions of ACh
- Direct Cholinergic Agonists: drugs that act at receptors
- Indirect Cholinergic Agonists: drugs that inhibit the metabolism of Ach and increase its level in synapses and increases the actions of ACh
what are the Direct cholinergic agonists drugs?
- Bethanechol
- Carbachol
- Methacholine
- Pilocarpine
what are the Indirect cholinergic agonists drugs?
- Neostigmine
- Physostigmine
- Pyridostigmine
- Edrophonium
- Tacrine
- Donepezil
- Ecothiophate
- Malathion
- Parathion
- Sarin
what indirect cholinergic agonist gets used in alzheimer’s?
Tacrine, Donepezil
what indirect cholinergic agonist are used as insecteside?
Malathion, Parathion
what indirect cholinergic agonist is used as nerve gas?
sabrin
why does Acetylcholine have no clinical use?
Because of non-specific actions & rapid inactivation by acetylcholinesterases
Methacholine is used to diagnose what? what do you call the test?
What type of action does it have? (does it bind muscarinic or nicotinic receptors more?)
bronchial asthma
methacholine challenge test
It has strong Muscarinic action & least or no Nicotinic action
what are the therapeutic uses of Bethanechol?
- Paralytic ileus: condition characterised by reduced bowel movements. mostly seen in post-op patients
- Urinary retention: Typically seen in postoperative patients and many other neurological diseases
what is Pilocarpine?
what type of receptor does it utilize?
is it water or lipid soluble?
what organ does it penetrate easily?
what are its therapeutic uses?
an alkaloid
It has Muscarinic activity only
lipid soluble
cornea
- glaucoma
- Sjogren syndrome: xerostomia (dry mouth), dry eye (keratoconjunctivitis) and arthritis
what Indirect Cholinergic agonists are reversible?
- Neostigmine
- Physostigmine
- Pyridostigmine
- Edrophonium
- Tacrine
- Donepezil
what Indirect Cholinergic agonists are irreversible?
- Ecothiophate
- Malathion
- Parathion
- Sarin
how long do reversible enzyme inhibitors act?
how long do irreversible enzyme inhibitors act?
of the irreversible indirect cholinergic agonist list, which one is used clinically? for what is it used?
short period of time
long period of time
Ecothiopate, is used for glaucoma
what drugs are used in sjogren, alzheimers, glaucoma?
what category are these? (reversible or irreversible?)
what drug is used in glaucoma? why?
pilocarpine and donepazil/tacrine
Reversible Cholinesterase inhibitors
Physostigmine, it penetrates the cornea well due to lipid solubility
why cant neostigmine be used in the treatment of glaucoma?
it is lipid insoluble and cant penetrate cornea too well
what is the mechanism of action of physostigmine?
reversible inhibition of AChE enzyme (↑ Ach)
what acetyl cholinesterase inhibitors are used in the treatment of myasthenia gravis?
which do you use only to diagnose myasthenia gravis?
- Neostigmine
- Pyridostigmine
Edrophonium
when is neostigmine used in Myasthenia gravis?
when is pyridostigmine used in myasthenia gravis?
when is Edrophonium used in myasthenia gravis?
it is used in acute cases
maintenance/ long term therapy due to longetivity of drug
shortest acting drug, so it is used in diagnosis of M. Gravis
how do you differentiate myasthenic crisis and cholinergic crisis?
what is another name for the test used to differentiate myasthenic crisis and cholinergic crisis?
use Edrophonium in small amount and there is contraction of muscle then it is myasthenic crisis since in cholinergic crisis the muscles would be more flaxid and not respond
tensilon test
If drug therapy is inadequate during myasthenic crisis, patients develop what?
what happens If excessive amounts of drugs have been used in patients with cholinergic crisis?
severe muscle weakness.
patients may become paradoxically weak because of nicotinic depolarizing blockade of the motor end plate.
what is belladona poisoning?
what symptoms can be seen?
the same thing as atropine poisoning, blocking muscarinic receptors
tachycardia, constipation, dry eye, dry mouth, urinary retention, dilated pupils
Tacrine, Rivastigmine and Donepezil, Malathion, Parathion…of these, which is used in the treatment of alzheimer’s?
what about the other 2 options?
what type of drug is the answer for the first question?
Tacrine, Rivastigmine and Donepezil
they are used as insectisides
irreversible acetylcholinesterase inhibitor
what are organophosphates?
signs and symptoms of organophosphate poisoning are due to what?
symptoms occur due to what?
what are the symtoms of organophosphate poisoning?
irreversible cholinesterase inhibitors
Phosphorylation (irreversible inhibition ) of the enzyme resulting in excess acetylcholine
stimulation of muscarinic receptors
miosis, blurred vision, bradycardia, salivation, sweating, urination, bronchial constriction, vomiting, and diarrhea
what is the drug of choice for organophosphate poisoning? why?
what is the problem of giving atropine alone?
what is given as well during Org. Phosphate poisoning?
Atropine a muscarinic receptor blocker is used to control signs of muscarinic excess stimulation of OP compounds.
- it cannot control the nicotinic effects OP poisoning
- can’t reverse the CNS effects
Pralidoxime: a Acetylcholine esterase reactivator that acts by hydrolysing (reactivating) the drug bound enzyme
what are the symptoms of Org. Phosphate poisoning?
DUMBELSS
- Diarrhea, Abdominal cramps, vomiting,
- Urination
- Miosis
- Bradycardia
- Bronchospasm
- Excitation of Skeletal muscle
- Lacrimation
- Salivation
- Sweating
