Potassium-sparing diuretics: Uses, common brands, and safety info

If you have high blood pressure (hypertension) or heart failure, a diuretic may be one of the medications you take. Diuretics are common medications for these conditions. Diuretics are usually prescribed by your primary healthcare provider or doctor of cardiology.

In terms of diuretics, there are several categories. Diuretics help the kidneys eliminate excess sodium and water through diuresis. Types of diuretics include loop diuretics (such as furosemide), thiazide diuretics (such as hydrochlorothiazide), carbonic anhydrase inhibitors, and potassium-sparing diuretics. 

This article will discuss uses, common brand names, and safety information of potassium-sparing diuretics. The table below lists potassium-sparing diuretics.

Combination potassium-sparing diuretics

In addition to the medications above, three potassium-sparing diuretics are also available as a combination product. Spironolactone, triamterene, and amiloride are also formulated as combination products with hydrochlorothiazide, which is a thiazide diuretic. Thiazide diuretics work in the distal convoluted tubule of the kidneys. This list is for reference—in this article, we will focus on the single ingredient potassium-sparing diuretics listed in the chart above. The combination potassium-sparing diuretics are: 

• Aldactazide (spironolactone/hydrochlorothiazide)

• Dyazide (triamterene/hydrochlorothiazide capsules)

• Maxzide (triamterene/hydrochlorothiazide tablets)

• Moduretic (amiloride/hydrochlorothiazide)

What are potassium-sparing diuretics?

Diuretic medications lower the amount of salt and water in the body. They facilitate the excretion of excess water and salt through the kidneys. Diuretics are used for conditions such as high blood pressure, edema (swelling or water retention), or congestive heart failure. 

Unlike other diuretics, potassium-sparing diuretics do not cause the body to lose potassium. Potassium-sparing diuretics are often prescribed in combination with another diuretic, most often hydrochlorothiazide. (See combination product list above.) 

How do potassium-sparing diuretics work?

Potassium-sparing diuretics work in different ways.  Amiloride and triamterene work on the sodium channels in the epithelial cells in the kidneys. These drugs have a weak diuretic effect and are usually used with another diuretic.

Spironolactone and eplerenone have a different mechanism of action. They are known as aldosterone receptor antagonists. They inhibit aldosterone from binding to the mineralocorticoid receptor on the epithelial cells in the kidney.

What are potassium-sparing diuretics used for?

Amiloride

Amiloride is rarely used alone due to its weak diuretic and blood pressure effects, and the possibility of causing high potassium levels. Amiloride is generally used along with another diuretic in patients with heart failure or high blood pressure. In these patients, amiloride is used to:

• Restore normal potassium levels in patients with low potassium (hypokalemia)

• Prevent the development of hypokalemia in high-risk patients

Eplerenone

Eplerenone may be used alone or in combination with other medications. Indications of eplerenone include:

• To improve survival in patients with heart failure after a heart attack (myocardial infarction)

• To lower blood pressure, which lowers the risk of cardiovascular events such as strokes and heart attacks

Spironolactone

Spironolactone is indicated for:

• Treatment of heart failure to increase survival, manage swelling, and prevent hospitalization (usually given with other heart failure medications)

• Hypertension (in combination with another medication or medications)

• Edema is associated with liver cirrhosis or nephrotic syndrome or when other diuretics have caused low potassium levels

• Primary hyperaldosteronism

Triamterene

Triamterene may be used alone or with another diuretic. It is indicated to treat:

• Edema associated with heart failure, liver cirrhosis, and nephrotic syndrome

• Edema caused by steroids

• Idiopathic edema

• Edema due to secondary hyperaldosteronism

Types of potassium-sparing diuretics 

Amiloride and triamterene

Amiloride and triamterene are potassium-sparing diuretics that have a weak diuretic effect. They are often used in combination with another diuretic to enhance their activity and prevent low potassium levels. They work by blocking the epithelial sodium channel in the distal tubule and collecting ducts of the kidneys.

Spironolactone and eplerenone

Spironolactone and eplerenone are known as aldosterone antagonists. They work by blocking the mineralocorticoid receptor in the distal tubule and collecting ducts of the kidneys. 

Who can take potassium-sparing diuretics?

The following information is a general overview of who can take potassium-sparing diuretics. As each person is different, consult your healthcare professional for medical advice. 

Men

Men can take potassium-sparing diuretics, provided they fall into one of the indicated categories, and that there is no contraindication for use. A contraindication is when using the drug could potentially harm the person. 

Women

Women (who are not pregnant or breastfeeding) can take potassium-sparing diuretics, provided they fall into one of the indicated categories and that there are no contraindications for use. 

Pregnancy 

Consult your doctor if you are pregnant or planning to become pregnant.

There are no well-controlled studies in pregnant women with amiloride and eplerenone, so these drugs should be used only if the benefits outweigh the risks. Eplerenone may also affect male fertility.

Spironolactone should not be used in pregnancy due to the possibility of effects on an unborn baby. 

Triamterene has not been studied in women, but it is recommended that triamterene not be used in pregnancy. Females of childbearing age should ask their doctor about folic acid supplementation before conceiving. 

Breastfeeding

Consult your doctor if you are breastfeeding.

In breastfeeding women, since the effects are unknown, the prescribing information recommends breastfeeding women either stop using amiloride and triamterene or stop nursing.

Eplerenone is present in the milk in animal studies, which means it is likely to be present in human milk. However, there is no official recommendation given in the prescribing information. 

Spironolactone does not seem to affect breastfed infants with short-term use, but long-term effects are not known.

Children

Amiloride, spironolactone, triamterene safety and efficacy have not been studied in children.

Some trials have studied eplerenone use in children and found it to be ineffective for lowering blood pressure. It has not been studied in pediatric heart failure patients.

Older adults

The prescribing information for amiloride recommends cautious dosing in this age group, starting at the lower end of the dosing range. This is because older adults are more likely to have decreased liver, kidney, or heart function; other conditions; and take other medications. The risk of toxic reactions is higher in people with impaired kidney function. Kidney function should be monitored while taking amiloride.

Studies of eplerenone for heart failure after a heart attack showed that patients over 75 years old did not benefit from this drug. There was an increased incidence of high potassium levels in patients 65 years and older. In patients with high blood pressure, there may be a higher risk of hyperkalemia in older adults.

Because spironolactone is greatly excreted by the kidneys, the risk of side effects is higher in patients with impaired kidney function. Older adults are more likely to have decreased kidney function. Kidney function should be monitored when taking spironolactone. 

Triamterene: Caution should be used in patients 65 years or older taking triamterene. 

Are potassium-sparing diuretics safe?

Recalls

Spironolactone recall (March 9, 2021)

Restrictions and warnings

Restrictions and warnings vary by specific drug. The following lists cover general warnings and restrictions. Tell your doctor about all of your medical conditions and history, as well as all of the medications you take, including prescription drugs, over-the-counter medicines, and vitamins or supplements. 

Do not take potassium-sparing diuretics if you:

• Are allergic to any ingredient in the drug

• Have high potassium (hyperkalemia)

• Have diabetic nephropathy

• Have kidney impairment.*

• Cannot pass urine

• Have Type 2 diabetes with microalbuminuria

• Have Addison’s disease

• Are pregnant (spironolactone, triamterene)

*The level/measure of kidney impairment varies by drug. Standard measures of kidney function include estimated glomerular filtration rate (eGFR), creatinine clearance (CrCl), blood urea nitrogen (BUN), and serum creatinine. Consult your healthcare provider regarding kidney function and potassium-sparing diuretics.

Potassium-sparing diuretics should be used with caution if you:

• Have diabetes mellitus

• Are an older adult

• Have liver impairment

• Have heart failure

• Have gout

• Have electrolyte abnormalities

• Are dehydrated

Potassium-sparing diuretics can increase potassium levels. This is called hyperkalemia. Hyperkalemia is more likely to occur in people with kidney problems, diabetes, older adults, or severely ill patients. 

Hyperkalemia is also more likely to occur when a potassium-sparing diuretic is taken with certain other medications such as ACE inhibitors or angiotensin receptor blockers. 

Symptoms of hyperkalemia include a tingling sensation, muscle weakness, paralysis of the extremities, slow heart rate, shock, and in more severe cases, an abnormal EKG. 

Because untreated hyperkalemia can be fatal, potassium levels must be frequently monitored when taking a potassium-sparing diuretic, and also if the dose is changed or if there is an illness that can affect kidney function. 

Do not use potassium supplements or salt substitutes that contain potassium without asking your doctor. 

Call your doctor right away or seek emergency medical attention if you experience dizziness, diarrhea, vomiting, irregular heartbeat, swelling of the lower extremities, or difficulty breathing. 

Are potassium-sparing diuretics controlled substances?

No, potassium-sparing diuretics are not controlled substances.

Common potassium-sparing diuretics side effects

Common side effects of potassium-sparing diuretics include:

• Headache

• Weakness

• Nausea/vomiting/diarrhea

• Abdominal pain or cramps

• Electrolyte imbalance

• High levels of potassium in the blood (hyperkalemia)

• Low levels of sodium in the blood (hyponatremia)

• High levels of uric acid in the blood (hyperuricemia)

• High cholesterol (hyperlipidemia)

• Increased creatinine levels

• Flatulence

• Appetite loss

• Dry mouth

• Muscle cramps

• Dizziness 

• Confusion 

• Tiredness 

• Flulike symptoms/fever

• Cough 

• Shortness of breath 

• Itching/rash 

• Impotence/sexual problems

• Vaginal bleeding/menstrual irregularities 

• Swollen breast tissue in men—gynecomastia (spironolactone)

• Breast pain (spironolactone)

• Stomach bleeding/ulcer (spironolactone)

Serious side effects of potassium-sparing diuretics include (some may be both common and serious):

• Hyperkalemia (can be severe)

• Low neutrophil count (neutropenia)

• The body stops making enough new cells (aplastic anemia)

Spironolactone is known to have more endocrine side effects such as breast pain, irregular menstrual cycles, and in men, swelling of breast tissue. Additional serious side effects of spironolactone include:

• Severe, life-threatening allergic reaction (anaphylaxis)

• A rare disorder of the skin and mucus membranes (Stevens-Johnson syndrome)

• Life-threatening skin disorder with peeling and blistering (toxic epidermal necrolysis)

• High eosinophil count

• Inflammation of blood vessels (vasculitis)

• Liver damage

• Kidney failure 

• Irregular heartbeat (arrhythmia)

• Low white blood cell count (leukopenia)

• Severe reduction in a type of white blood cells called granulocytes (agranulocytosis)

• Low platelets (thrombocytopenia)

Additional serious side effects of triamterene:

• Severe, life-threatening allergic reaction (anaphylaxis)

• Ventricular arrhythmia

• Kidney failure 

• Low platelets (thrombocytopenia)

• Inflamed kidneys (interstitial nephritis)

• Very large, malformed red blood cells (megaloblastic anemia)

Report side effects to your doctor. This is not a complete list of side effects. Consult your healthcare professional for a full list of side effects. 

How much do potassium-sparing diuretics cost?

Potassium-sparing diuretics are all available in generic form. This significantly reduces the cost, making this class of drugs very affordable. 

Contact your health insurance plan or Medicare prescription plan for up-to-date coverage information. You can always use a free SingleCare card or coupon when filling and refilling your potassium-sparing diuretic prescription. People who use SingleCare can save up to 80% on prescription costs.