Pharmacology - Comprehensive Mock Test 10

Question 91 Hard

Which of the following is a relatively cerebroselective anticholinesterase found to afford symptomatic improvement in Alzheimer's disease

A) Donepezil B) Gemfibrozil C) Pyridostigmine D) Pyritinol

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Question 92 Medium

Edrophonium is more suitable for differentiating myasthenic crisis from cholinergic crisis because of its

A) Shorter duration of action B) Longer duration of action C) Direct action on muscle end-plate D) Selective inhibition of true cholinesterase

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Question 93 Medium

The mechanism by which neostigmine improves contraction of myasthenic muscle involves

A) Repetitive binding of the acetylcholine molecules to the same receptors at the muscle endplate B) Diffusion of acetylcholine released from motor nerve endings to a wider area activating neighbouring receptors C) Activation of motor end-plate receptors by neostigmine molecules themselves D) All of the above

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Question 94 Medium

Neostigmine is preferred over physostigmine for treating myasthenia gravis because

A) It is better absorbed orally B) It has longer duration of action C) It has additional direct agonistic action on nicotinic receptors at the muscle end plate D) It penetrates blood-brain barrier

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Question 95 Hard

Out of two anticholinesterases, drug ‘X’ is a tertiary amine while drug ‘Y’ is a quarternary ammonium compoun4⃣ Then

A) Drug ‘X’ is likely to be more potent than ‘Y’ B) Drug ‘X’ will be more suitable to be used as a miotic C) Drug ‘Y’ will be completely metabolized in the body D) Then?1⃣ Drug ‘X’ is likely to be more potent than ‘Y’ 2⃣ Drug ‘X’ will be more suitable to be used as a miotic 3⃣ Drug ‘Y’ will be completely metabolized in the body

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Question 96 Medium

The organophosphates produce irreversible inhibition of cholinesterase because

A) They bind to an allosteric site of the enzyme resulting in unfavourable conformation of esteratic site to bind acetylcholine B) Regeneration time of the phosphorylated enzyme is longer than the turnover time of the enzyme molecules C) Phosphorylation results in rapid degradation of enzyme molecules D) They are neither metabolized nor excreted from the body

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Question 97 Medium

The anticholinesterase action of edrophonium is short lasting because termination of its action depends on

A) Dissociation and diffusion of the drug from the enzyme B) Hydrolysis of the drug by the enzyme C) Synthesis of fresh enzyme molecules D) A combination of the above three processes

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Question 98 Hard

Reactivation of cholinesterase enzyme occurs on hydrolysis of the inhibitor by the same enzyme molecule in case of the following anticholinesterase

A) Edrophonium B) Neostigmine C) Dyflos D) Tacrine

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Question 99 Medium

The following inhibitor binds only to the ani-onic site of the cholinesterase enzyme

A) Neostigmine B) Physostigmine C) Edrophonium D) Dyflos

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Question 100 Medium

Actions of pilocarpine include the following <u>except</u>

A) Sweating B) Salivation C) Miosis D) Cycloplegia

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