Anticholinesterases in Pharmacology
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Questions and Answers

What is the origin of Physostigmine?

  • Natural alkaloid (correct)
  • Synthetic derivative
  • Fermentation product
  • Semi-synthetic derivative

    • What is the difference in solubility between Physostigmine and Neostigmine?

  • Neostigmine is highly lipid soluble, Physostigmine is not
  • Both are not lipid soluble
  • Physostigmine is highly lipid soluble, Neostigmine is not (correct)
  • Both are highly lipid soluble

    • What is a common use of Physostigmine?

  • Myasthenia gravis
  • Post-operative paralytic ileus
  • Belladonna (atropine) poisoning
  • All of the above (correct)

    • Which of the following is used in the diagnosis of myasthenia gravis?

    <p>Edrophonium</p> Signup and view all the answers

    What is the effect of muscarinic poisoning on the eyes?

    <p>Miosis</p> Signup and view all the answers

    What is the characteristic of Donepezil?

    <p>Lipid soluble, long acting</p> Signup and view all the answers

    What is the main goal of rapid decontamination in op poisoning?

    <p>To prevent further absorption of the toxin</p> Signup and view all the answers

    What is a common adverse effect of cholinomimetics?

    <p>SLUDGE syndrome</p> Signup and view all the answers

    What happens to the covalent bonding between AchE and organophosphates during aging?

    <p>It becomes more stable and irreversible</p> Signup and view all the answers

    What is the golden period for reactivation of AchE in op poisoning?

    <p>Within 2 hours of exposure</p> Signup and view all the answers

    What is the function of oximes in op poisoning management?

    <p>To reactivate cholinesterase</p> Signup and view all the answers

    What is the use of Neostigmine in anesthesia?

    <p>Reversal of muscle relaxation</p> Signup and view all the answers

    What is a characteristic of Organophosphates?

    <p>Irreversible inhibitor of AchE</p> Signup and view all the answers

    What type of drugs are pilocarpine and physostigmine?

    <p>Parasympathetic agents</p> Signup and view all the answers

    What is the effect of nicotinic poisoning on the muscles?

    <p>All of the above</p> Signup and view all the answers

    What is a CNS effect of cholinomimetics?

    <p>CNS stimulation</p> Signup and view all the answers

    What is the role of atropine in op poisoning management?

    <p>To block the actions of acetylcholine</p> Signup and view all the answers

    What is the mechanism of action of anticholinesterases?

    <p>Inhibit AchE</p> Signup and view all the answers

    What is the primary cause of death in severe acute op poisoning?

    <p>Cardiopulmonary failure</p> Signup and view all the answers

    What is the function of suctioning bronchial secretions in op poisoning management?

    <p>To reduce bronchospasm</p> Signup and view all the answers

    What is the result of inhibiting AchE?

    <p>Prolonged duration of action of ACh</p> Signup and view all the answers

    What is the role of diazepam in op poisoning management?

    <p>To control convulsions</p> Signup and view all the answers

    What is the characteristic of reversible AchE?

    <p>Structurally similar to ACh</p> Signup and view all the answers

    What is the effect of anticholinesterases on the synaptic space?

    <p>Increased accumulation of ACh</p> Signup and view all the answers

    What is the use of physostigmine and neostigmine?

    <p>All of the above</p> Signup and view all the answers

    What is the adverse effect of cholinomimetic drugs?

    <p>Increased salivation</p> Signup and view all the answers

    What is the rationale for using atropine in the management of organophosphorus poisoning?

    <p>Atropine is an antagonist of ACh</p> Signup and view all the answers

    What is the manifestation of organophosphorus poisoning?

    <p>Cholinergic crisis</p> Signup and view all the answers

    What is the management of organophosphorus poisoning?

    <p>All of the above</p> Signup and view all the answers

    What are the groups of drugs used in glaucoma?

    <p>All of the above</p> Signup and view all the answers

    Study Notes

    Mechanism of Action of Anticholinesterases

    • Anticholinesterases (AchE) inhibit the breakdown of acetylcholine (ACh) in the synaptic space, leading to an increase in ACh levels.
    • Reversible AchE inhibitors, such as physostigmine and neostigmine, have a similar structure to ACh and bind to the enzyme, temporarily inhibiting it.
    • This indirect mechanism allows ACh to accumulate in the synaptic space, leading to a cholinergic effect.

    Physostigmine vs Neostigmine

    • Physostigmine:
    • Natural alkaloid
    • Tertiary amine structure
    • Highly lipid soluble, allowing it to cross the blood-brain barrier
    • Can cause convulsions at high doses
    • Neostigmine:
    • Synthetic derivative
    • Quaternary amine structure
    • Not lipid soluble, unable to cross the blood-brain barrier
    • Less likely to cause convulsions even at high doses

    Therapeutic Uses of Reversible Anticholinesterases

    • Alzheimer's disease: Galantamine, Tacrine, Donepezil, Rivastigmine
    • Myasthenia gravis: Neostigmine, Pyridostigmine
    • Post-operative reversal of muscle relaxation: Neostigmine
    • Atropine poisoning: Physostigmine

    Uses of Cholinomimetics

    • Edrophonium: Short-acting, diagnosis of myasthenia gravis
    • Physostigmine: Intermediate-acting, treatment of glaucoma and atropine poisoning
    • Neostigmine: Intermediate-acting, treatment of paralytic ileus, urinary retention, myasthenia gravis, and reversal of non-depolarizing neuromuscular blockers
    • Donepezil: Lipid soluble, treatment of Alzheimer's disease
    • Organophosphates: Irreversible inhibitors, used as insecticides and nerve gas

    Adverse Effects of Cholinomimetics

    • SLUDGE syndrome: Salivation, lacrimation, urination, defecation, gastrointestinal upset, and emesis
    • CNS stimulation
    • Miosis and spasm of accommodation
    • Bronchoconstriction and tracheobronchial secretions
    • AV block

    Organophosphate Poisoning and Management

    • Muscarinic symptoms: Diarrhea, urination, miosis, bronchospasm, bradycardia, lacrimation, emesis, and sweating
    • Nicotinic symptoms: Muscle fatigue and weakness, twitching, fasciculation, tremors, muscle paralysis
    • CNS symptoms: Ataxia, confusion, convulsions, depressed respiration, and cardiovascular function
    • Initial treatment: Rapid decontamination, maintaining respiration, suction of bronchial secretions, catheterization of the urinary bladder, and control of convulsions
    • Atropine: Antimuscarinic agent, blocks all actions of ACh on muscarinic receptors
    • Oximes: Cholinesterase reactivators, reactivate AchE inhibited by organophosphates

    Reactivation of AchE by Oximes

    • Golden period: Within 2 hours of exposure, oximes can prevent aging and reactivate AchE

    Drugs Used in Glaucoma

    • Parasympathetic agents: Pilocarpine, physostigmine, dipivefrin, apraclonidine, and brimonidine
    • Adrenergic agonists: Timolol, levobunolol, carteolol
    • Beta blockers: Timolol, levobunolol, carteolol
    • Carbonic anhydrase inhibitors: Acetazolamide, dorzolamide
    • Prostaglandin analogs: Latanoprost, travoprost
    • Osmotic agents: Mannitol, glycerin

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    Cholinomimetics Study Notes PDF

    Description

    This quiz covers the mechanism of action, uses, and adverse effects of anticholinesterases, including physostigmine and neostigmine, in conditions like Alzheimer's and myasthenia gravis.

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