Pharmacology mcqs (final control) 3rd course

= Pheochromocytoma

~ Chronic hypertension
224- The main reason for using alfa-receptor antagonists in the management of pheochromocytoma is:
~ Inhibition of the release of epinephrine from the adrenal medulla

= Blockade of alfa₂ receptors on vascular smooth muscle results in epinephrine stimulation of unblocked alfa₂ receptors

~ Direct interaction with and inhibition of beta₂ adrenoreceptors
~ Antagonism to the release of renin
225-Which of the following drugs is useful in the treatment of pheochromocytoma?
~ Phenylephrine
~ Propranolol

= Phentolamine

~ Epinephrine
226- Indicate adrenoreceptor antagonist agents, which are used for the management of pheochromocytoma:
~ Selective beta₂-receptor antagonists
~ Nonselective beta-receptor antagonists
~ Indirect-acting adrenoreceptor antagonist drugs

= Αlfa-receptor antagonists

227- The principal adverse effects of phentolamine include all of the following EXCEPT:
~ Diarrhea

= Bradycardia

~ Arrhythmias
~ Myocardial ischemia
228-Indicate the reversible nonselective alfa-receptor antagonist, which is an ergot derivative:

= Ergotamine

~ Prazosin
~ Phenoxybenzamine
~ Carvedilol
229- Indicate an alfa-receptor antagonist, which binds covalently to alfa receptors, causing irreversible blockade of long duration (14-48 hours or longer):
~ Phentolamine

= Phenoxybenzamine

~ Ergotamine
~ Prazosin
230- Compared with phentolamine, prazosin has all of the following features EXCEPT:

= Irreversible blockade of alfa receptors

~ Highly selective for alfa₁ receptors
~ The relative absence of tachycardia
~ Persistent block of alfa₁ receptors
231- Which of the following statements is not correct?
~ There are at least three subtypes of alfa₁ receptors, designated alfa_1a, alfa_1b and alfa_1d
~ ALFA_1a subtype mediates prostate smooth muscle contraction
~ ALFA_1b subtype mediates vascular smooth muscle contraction