Diuretic Drugs Overview

Drugs designed to increase urine production, leading to fluid removal from the body. They often target sodium and water excretion, making them useful for treating hypertension, heart failure, and kidney problems.

Diuretics work at specific locations within the nephron, the functional unit of the kidney. Each diuretic class has its primary site of action.

Diuretics are categorized by their mechanism of action: Carbonic anhydrase inhibitors, Loop diuretics, Osmotic diuretics, Potassium-sparing diuretics, Thiazide and thiazide-like diuretics.

A class of diuretics that block the action of carbonic anhydrase, an enzyme in the kidneys involved in reabsorbing sodium and water. This leads to increased excretion of bicarbonate, sodium, water, and potassium.

The most commonly used carbonic anhydrase inhibitor (CAI) diuretic.

This group includes Bumetanide (Bumex), Ethacrynic acid (Edecrin), Furosemide (Lasix), and Torsemide (Demadex). They block sodium/chloride reabsorption in the ascending limb of the Loop of Henle.

Furosemide (Lasix) is the most commonly used loop diuretic.

Common uses include treating pulmonary edema (fluid in the lungs), heart failure-related edema, liver disease-related edema, nephrotic syndrome (kidney disorder), ascites (fluid buildup in the abdomen), and hypertension.

Significant fluid loss can lead to reduced blood pressure, pulmonary vascular resistance, systemic vascular resistance, central venous pressure, and left ventricular end-diastolic pressure. Potassium and sodium depletion can also occur.

Loop diuretics work in the Loop of Henle to block sodium/chloride reabsorption and prevent water uptake. They also increase prostaglandins, leading to blood vessel dilation and reduced peripheral vascular resistance. They can still cause diuresis even with kidney damage.

These diuretics, like Mannitol (Osmitrol), Urea, organic acids, and glucose, work mainly in the proximal tubule. They pull water into renal tubules from surrounding tissues.

The most commonly used osmotic diuretic, available in an IV form only.

Osmotic diuretics are non-absorbable, creating an osmotic pressure that pulls water into the renal tubules from surrounding tissues. This inhibits reabsorption of water and solutes, causing rapid diuresis.

Common uses include treating the early, oliguric phase of acute renal failure (ARF), promoting excretion of toxic substances, reducing intracranial pressure, and treating cerebral edema.

This group includes Spironolactone, Triamterene, and Amiloride. They block aldosterone receptors, preventing potassium from leaving the body and aiding in sodium and water excretion.

Potassium-sparing diuretics are also known as aldosterone-inhibiting diuretics because they block the actions of aldosterone, a hormone that promotes potassium excretion.

They block aldosterone receptors to prevent potassium loss and promote sodium and water excretion.

Spironolactone and triamterene are commonly used for hyperaldosteronism, hypertension, reversing potassium loss caused by other drugs, and certain cases of heart failure. Amiloride is used for heart failure, but it's less effective long-term.

Potential side effects include CNS dizziness, headache, GI cramps, nausea, vomiting, diarrhea, urinary frequency, weakness, and hyperkalemia.

Interactions can occur with lithium, ACE inhibitors, potassium supplements, and NSAIDs.

This group includes Hydrochlorothiazide (Esidrix, HydroDIURIL) and Chlorothiazide (Diuril). They primarily target the distal convoluted tubule, inhibiting sodium, chloride, and potassium reabsorption.

This group includes Metolazone (Mykrox, Zaroxolyn), Chlorthalidone (Hydone, Thalitone), and Indapamide (Lozol). They have a similar mechanism of action to thiazides.

They inhibit tubular reabsorption of sodium, chloride, and potassium ions. They mainly work in the distal convoluted tubule. This results in water, sodium, and chloride excretion, with potassium excretion to a lesser extent. They also dilate arterioles.

Common uses include hypertension (one of the most prescribed groups for this), edematous states, idiopathic hypercalciuria, diabetes insipidus, heart failure due to diastolic dysfunction, and edema related to heart failure, hepatic cirrhosis, or steroid/estrogen therapy.

Potential side effects include CNS dizziness, headache, blurred vision, GI anorexia, nausea, vomiting, diarrhea, genitourinary impotence, hematologic jaundice, leukopenia, integumentary urticaria, photosensitivity, and metabolic hypokalemia, hyperglycemia, hyperuricemia, and hypochloremic alkalosis.

Symptoms of high potassium levels include dizziness, muscle cramps, cardiac irregularities, weakness, nausea, diarrhea.

Symptoms of low potassium include alkalosis, shallow respirations, irritability, confusion, drowsiness, weakness, arrhythmias (irregular heartbeat), lethargy, thready pulse, intestinal motility issues, nausea, vomiting, and ileus.