For the management of acute angina, which medication is preferred for immediate relief?

Choice A rationale

D5W (dextrose 5% in water) is an isotonic solution in the bag but becomes hypotonic in the body as dextrose is metabolized, leading to free water redistribution. This fluid is not ideal for dehydration as it does not contain electrolytes and can potentially dilute existing electrolytes, which is counterproductive for replacing lost volume and salts.

Choice B rationale

0.9% normal saline is an isotonic solution, meaning it has a similar concentration of solutes to the body's plasma. It is the most appropriate choice for treating dehydration, as it replenishes both fluid volume and sodium chloride, which are commonly lost during dehydration, effectively expanding the intravascular compartment without causing major fluid shifts.

Choice C rationale

0.45% saline, or half-normal saline, is a hypotonic solution with half the sodium concentration of normal saline. This fluid is used to replace free water deficits and for hypernatremia, but it is not the first-line choice for general dehydration as it does not effectively expand the intravascular volume and can cause fluid shifts into cells.

Choice D rationale

Packed red blood cells (PRBCs) are blood products used for anemia or significant blood loss to increase oxygen-carrying capacity. They are not a fluid replacement for dehydration. Administering blood when it's not clinically indicated for fluid volume deficit is inappropriate and carries risks of transfusion reactions and fluid overload.

Choice A rationale

Increasing the dose of losartan would exacerbate the patient's dizziness and hypotension. Losartan, an angiotensin II receptor blocker (ARB), works by blocking the vasoconstrictive effects of angiotensin II, leading to vasodilation and a decrease in blood pressure. An increased dose would lead to more profound vasodilation, resulting in an even greater drop in blood pressure and worsening orthostatic hypotension. This could increase the risk of falls and injury.

Choice B rationale

Losartan is a vasodilator, and its action can lead to a drop in blood pressure, especially when a person moves from a sitting or lying position to a standing position, a condition known as orthostatic hypotension. The dizziness is a symptom of this sudden drop in blood pressure. Changing positions slowly allows the body's baroreceptor reflex to compensate and regulate blood pressure, thus mitigating the orthostatic effect and preventing falls.

Choice C rationale

Taking losartan with food does not significantly alter its absorption or a patient's risk of orthostatic hypotension. Losartan can be taken with or without food. However, this action does not address the underlying physiological mechanism of orthostatic hypotension, which is a common side effect of this class of antihypertensive medications. The dizziness is directly related to the vasodilation effect, not food intake.

Choice D rationale

Discontinuing losartan abruptly without consulting a healthcare provider can be dangerous. It could lead to a rebound increase in blood pressure, or a hypertensive crisis, which can increase the risk of stroke or myocardial infarction. The patient should be advised to manage the side effect by changing position slowly, and if symptoms persist, they should consult their healthcare provider to discuss alternative medication options or dose adjustments.