Answer to Question 1
Correct Answer: 1,2
Rationale 1: Alpha1 antagonists block alpha1 receptors on arterial smooth muscle, which directly lowers blood pressure.
Rationale 2: Alpha1 antagonists dilate veins, which indirectly lowers the blood pressure by decreasing venous return to the heart.
Rationale 3: Although a few agents selectively block alpha2-adrenergic receptors, they are used for research purposes and have no clinical application.
Rationale 4: Beta blockers reduce the heart rate.
Rationale 5: Beta blockers reduce the force of myocardial contraction.
Global Rationale: Alpha1 antagonists block alpha1 receptors on arterial smooth muscle, which directly lowers blood pressure and they dilate veins, which indirectly lowers the blood pressure by decreasing venous return to the heart. Although a few agents selectively block alpha2-adrenergic receptors, they are used for research purposes and have no clinical application. Beta blockers reduce the heart rate and the force of myocardial contractions.
Answer to Question 2
Correct Answer: 2
Rationale 1: Sildenafil (Viagra) has no effect on the elimination of doxazosin.
Rationale 2: Use of doxazosin (Cardura) with erectile dysfunction agents such as sildenafil (Viagra) can cause increased hypotension, since both these drugs relax the smooth muscles of the vessels. Using both together can cause added hypotension.
Rationale 3: Sildenafil (Viagra) has no effect on the absorption of doxazosin through the gastrointestinal tract.
Rationale 4: Sildenafil (Viagra) does not cause hypertension but hypotension, due to relaxation of the smooth muscle.
Global Rationale: Use of doxazosin (Cardura) with erectile dysfunction agents such as sildenafil (Viagra) can cause increased hypotension, since both these drugs relax the smooth muscles of the vessels. Using both together can cause added hypotension. Sildenafil (Viagra) has no effect on the elimination of doxazosin; no effect on the absorption of doxazosin through the gastrointestinal tract; and does not cause hypertension but hypotension, due to relaxation of the smooth muscle.