A nurse understands that a common reason why a patient is prescribed a combination of diuretics is because?

Alpha 1 adrenergic blocking agents have a vasodilating effect and can be used for the management of hypertension.They work by preventing the hormone norepinephrine from tightening the muscles in the walls of smaller arteries and veins, thus lowering the blood pressure.Some examples of alpha 1 blockers are doxazosin, prazosin, and terazosin.

Choice A is wrong because alpha 3 adrenergic blockers do not exist.There are only two subtypes of alpha receptors: alpha 1 and alpha 2.

Choice B is wrong because alpha 2 adrenergic antagonists are not used for hypertension.They are used for conditions like attention deficit hyperactivity disorder (ADHD) and opioid withdrawal.Alpha 2 antagonists block the negative feedback mechanism of norepinephrine release, thus increasing the amount of norepinephrine in the blood and raising the blood pressure.

Choice C is wrong because alpha 1 adrenergic agonists have the opposite effect of alpha 1 blockers.They stimulate the alpha 1 receptors and cause vasoconstriction, which increases the blood pressure.Alpha 1 agonists are used for conditions like nasal congestion and hypotension.

Hypokalemia is a condition where the blood potassium level is too low, which can cause muscle weakness, arrhythmias, and other problems. Diuretics are drugs that increase urine output and help remove excess fluid from the body. Some diuretics, such as loop diuretics, also cause potassium loss in the urine.To prevent hypokalemia, a combination of diuretics may be prescribed, such as a loop diuretic with a potassium-sparing diuretic or a thiazide diuretic. These combinations help balance the potassium level while still removing sodium and water.

Choice A is wrong because they are not a part of the initial diuretic therapy.Combination diuretic therapy is usually reserved for patients who have resistant edema or hypertension that does not respond to monotherapy.

Choice C is wrong because they do not boost the blood-pressure-lowering effect of other medications.Diuretics can lower blood pressure by reducing blood volume and relaxing blood vessels, but they are not used to enhance the effect of other antihypertensive drugs.

Choice D is wrong because they do not have fewer side effects when used in a drug combination.Combination diuretic therapy can increase the risk of electrolyte imbalances, such as hyponatremia, hypokalemia, hypomagnesemia, and metabolic alkalosis.It can also cause hypotension, dehydration, and worsening renal function.Therefore, combination diuretic therapy should be used with caution and close monitoring.

Normal ranges for blood potassium level are 3.5 to 5.0 mmol/L or 3.5 to 5.0 mEq/L.Normal ranges for blood sodium level are 135 to 145 mmol/L or 135 to 145 mEq/L.

Normal ranges for blood pressure are less than 120/80 mm Hg for normal, 120-129/less than 80 mm Hg for elevated, 130-139/80-89 mm Hg for stage 1 hypertension, and 140 or higher/90 or higher mm Hg for stage 2 hypertension.