Question 9

Diuretics are prescribed to increase urine flow and decrease total blood volume that must be pumped.

Diuretics help patients with high blood pressure by promoting the excretion of water and sodium through urine, which reduces total blood volume and consequently lowers blood pressure.

A) To decrease urine flow, and to make the blood less viscous and easier to pump

This option is incorrect because diuretics are designed to increase urine flow rather than decrease it. Additionally, the viscosity of blood is not primarily addressed through diuretic use, as their main function is to reduce blood volume.

B) To increase urine flow, and to decrease total blood volume that must be pumped

This option is correct as diuretics facilitate increased urine production, which leads to a reduction in the total blood volume. By lowering blood volume, diuretics help to decrease blood pressure, making this the most suitable reason for prescribing them to hypertensive patients.

C) To increase urine flow, and to increase the total blood volume that must be pumped

This option is incorrect since increasing urine flow would not lead to an increase in total blood volume. In fact, the opposite occurs; increased urine output typically results in decreased blood volume, which is contrary to what this option suggests.

D) To decrease urine flow, and to decrease total blood volume that must be pumped

This option is inaccurate because diuretics are intended to increase urine flow, not decrease it. While they do lower blood volume, the mechanism of action is fundamentally misrepresented here.

Conclusion

The rationale for prescribing diuretics to patients with high blood pressure hinges on their ability to increase urine flow, which directly contributes to a decrease in total blood volume. This is why Option B is the correct choice, while the other options either misstate the functions of diuretics or present incorrect outcomes related to their use.