Q 1. As An Antiepileptic drug, Phenytoin is most similar in action to which one of the following drugs?
Answer: C (Lidocaine)
Explanations: Phenytoin and lidocaine are Both similar in action both are class IB Antiarrhythmic agents.These drugs slightly depress phase 0 and may shorten the duration of the action potential.They are most commonly used for the treatment of ventricular arrhythmia.
Q2.How does Clonidine, An Antihypertensive drug, Work?
(A)Block Alpha 1 Adrenergic Receptors
(B)Stimulate Alpha 2 Adrenergic Receptors In The Brain.
(C)Increase heart rate due to stimulation of SA Node
(D)Block Beta Adrenoceptors.
Answer: B (Stimulate alpha 2 adrenergic receptors in the brain)
Explanation: Clonidine stimulates the alpha 2 adrenergic receptors in the vasomotor center of the brain, leading to decrease in activity of sympathetic nerves to the peripheral tissues.Inhibition of the sympathetic nerves to the heart will lead to decrease in the cardiac output, and inhibition of the sympathetic nerves to the blood vessels will cause vasodilation.both of these effects will cause fall in the blood pressure.
Q.3 Phentolamine is a (an)
(A)Alpha 1 adrenergic antagonist
(B)Beta 2 adrenergic antagonist
(C)Both alpha 1+2 Antagonist
(D)Mainly Alpha 2 adrenergic antagonist.
Answer: C (Both alpha 1+2 Antagonist
Explanation: Phentolamine blocks both alpha 1 and alpha 2 receptors equally.Phentolamine blocks the alpha receptors for a short period of time and its blocking effect on the alpha receptors is reversible.
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