Best Edema Diuretics: Loop vs. Potassium Sparing

Loop Diuretics

Used in either oral form or through an I.V. in a hospital setting, loop diuretics have several effects. Their most basic function is increasing urine flow to remove water from the body. Loop diuretics do this better than any other diuretic. They are also more powerful than thiazides making them more effective for treating patients with impaired kidney function.

How do Loop Diuretics work?

Loop diuretics, “act at the ascending Loop of Henle (a tiny, loop-like filtering tube in the kidney nephrons) resulting in increased urine production, giving the medication its name. Specifically, loop diuretics prevent the reabsorption of sodium ions which increases electrolyte concentration in the fluid passing through the nephron.

This concentrated water cannot be put back into the bloodstream from the nephron. As a result, sodium reabsorption is inhibited which causes water to be lost as urine due to increased urine volume and urination frequency.

Uses of Loop Diuretics

Loop diuretics are powerful medications which are used to treat edema (swelling). They are used mainly in hospital patients who suffer from conditions like congestive heart failure, liver disease, and kidney disease.

They also reduce blood volume which decreases blood pressure. Because of this, they are sometimes used to treat hypertension (high blood pressure), especially in patients with congestive heart failure.

Risks and Side Effects of Loop Diuretics

Loop diuretics may be accompanied by the following side effects:

• Syncope - fainting
• Dizziness
• Orthostatic hypotension (postural hypotension) - falling blood pressure when a person suddenly stands up from a lying or sitting position
• Dehydration
• Gout - a type of inflammatory arthritis
• Hyponatremia - low sodium levels
• Hypokalemia - low potassium levels
• Hypomagnesemia - low magnesium levels
• Hyperuricemia - abnormally high levels of uric acid in the blood

Some infrequent side effects of these medications are:

• Hypocalcemia - low calcium in the blood
• Metabolic alkalosis - tissue pH elevated beyond the normal range
• Dyslipidemia - an abnormal amount of lipids (fats) in the blood
• Increased serum creatinine concentration
• Kidney failure (only in patients concurrently taking an NSAID and an ACE inhibitor)
• Ototoxicity - ear damage which might be limited to tinnitus and vertigo, but could also result in deafness
• Rash

In addition, some loop diuretics (furosemide, torsemide, and bumetanide) are sulfa drugs (sulfonamides). Those who are sensitive to sulfa drugs may also be sensitive to these medications. And although ethacrynic acid is not a sulfonamide, it has been linked to gastrointestinal toxicity.

Potassium-sparing Diuretics

Like other diuretics, potassium-sparing diuretics increase urination. However, unlike loop diuretics and thiazide diuretics, these diuretics reduce the amount of water and sodium in the body without lowering potassium levels. Potassium-sparing diuretics are less powerful than other diuretics. They can be used alone, but are frequently used alongside loop or thiazide diuretics.

How are Potassium-sparing Diuretics Used?

Like other diuretics, these medications can be used to treat hypertension (high blood pressure). They are also used to address low potassium levels. In addition, they are frequently used to treat liver disease and abdominal fluid build-up caused by liver damage.

Side Effects

Some of the more common side effects of potassium-sparing diuretics are listed below:

• Hyperkalemia - too much potassium in the body (if used with other medications which help the body retain potassium).
• Hyponatremia - low sodium levels
• Hypochloremia - low chlorine levels
• Weakness
• Headaches
• Nausea
• Vomiting
• Constipation
• Dizziness
• Muscle cramps
• Frequent urination
• Abnormal glucose levels