Spironolactone dosage, forms, and strengths

Spironolactone, known by the brand name Aldactone, is a potassium-sparing diuretic sometimes referred to as a “water pill.” By producing more urine, spironolactone treats conditions that cause the body to hold water. These conditions include high blood pressure, congestive heart failure, edema, or low serum potassium levels (hypokalemia).

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Spironolactone forms and strengths 

• Tablets: 25 mg, 50 mg, 100 mg

• Liquid suspension: 25 mg/5 mL

Spironolactone dosage for adults

Below are standard spironolactone oral doses for adults with a maximum daily dosage of 400 mg for all conditions. Dosage is typically modified for those with liver and kidney disease.

Spironolactone dosage for heart failure

Spironolactone can help people with heart failure by improving their symptoms. It improves the heart’s structure (myocardial) muscle fibers, reduces heart muscle (myocyte) cell death, and reduces myocardial inflammation. In a 2018 clinical trial known as the RALES trial, spironolactone reduced the risk of all causes of mortality by 35% in individuals with heart failure with reduced ejection fraction (HFrEF). A typical dose of spironolactone for HFrEF is 25 to 50 mg once per day. 

Spironolactone dosage for hypertension (high blood pressure)

Spironolactone can manage resistant hypertension, which is hypertension that hasn’t improved using at least three medications with one being a diuretic. In a 2015 study published in Lancet and NEJM, spironolactone lowered the average systolic blood pressure by 8.7 mm Hg compared to a placebo. 

Spironolactone reduces blood pressure by helping the body eliminate excess salt and water while retaining potassium. The lower blood volume and retained potassium have the additional benefit of reducing strain on the heart. In this instance, spironolactone acts as a diuretic and an antihypertensive agent. A typical dose of spironolactone for hypertension is 25 to 100 mg spread out over two to four doses throughout the day. 

Spironolactone dosage for edema

Spironolactone blocks the activity of the hormone aldosterone, making it an “aldosterone antagonist.” People with too much aldosterone retain salt and water in their bodies, which can cause edema. Edema often occurs as a complication of congestive heart failure, liver cirrhosis, or kidney disorders like nephrotic syndrome. Symptoms include uncomfortable or even disfiguring swelling in the hands, feet, arms, and legs. Spironolactone can help by eliminating the excess water and reducing or eliminating the edema. A typical dose of spironolactone for edema is 25 to 200 mg spread out over one to two doses throughout the day. 

Spironolactone dosage for ascites due to liver cirrhosis

Ascites is an accumulation of fluid in the abdomen. It is a common and uncomfortable complication of liver cirrhosis and liver failure. Ascites is a late sign of cirrhosis and is usually associated with advanced disease. Spironolactone can help individuals with ascites by eliminating the excess fluid in the abdomen through the kidneys. The body eliminates the fluid through the urine. A typical dose of spironolactone for ascites is 100 to 400 mg spread out over one to four doses throughout the day. 

Spironolactone dosage for primary hyperaldosteronism

The main function of aldosterone is to regulate the amount of salt in the body. Aldosterone also causes the body to reabsorb water with the salt. Individuals who have too much aldosterone have a condition called hyperaldosteronism. 

Primary hyperaldosteronism is when adrenal glands make too much aldosterone. Spironolactone is considered the most effective medication for controlling the effects of primary hyperaldosteronism.A typical dose of spironolactone for primary hyperaldosteronism is 100 to 400 mg once per day. 

Spironolactone dosage for diuretic-induced hypokalemia

Hypokalemia occurs when the body does not have enough potassium, which can cause heart problems. There are various causes of hypokalemia, one of which is a side effect of general diuretic use. However, spironolactone is a “potassium-sparing” diuretic that helps minimize the amount of potassium excreted in the urine. Serum potassium less than or equal to 5 mEq/L is an indication for using spironolactone over another diuretic.A typical dose of spironolactone for diuretic-induced hypokalemia is 25 to 100 mg spread out over one to four doses throughout the day. 

Spironolactone dosage for hirsutism 

Hirsutism is a condition in women that causes an excess of dark, thick, or coarse hair in a male pattern or male distribution in the body (over the face, chest, and back). Hirsutism occurs due to an excess of androgen hormones, like testosterone, circulating in a woman’s body. 

Spironolactone blocks the androgen receptors in various tissues, decreases testosterone production, and prevents any circulating testosterone from affecting its target tissue. The result is reduced unwanted hair. A typical dose of spironolactone for hirsutism is 50 to 200 mg once per day.

Spironolactone dosage for acne vulgaris 

Acne vulgaris commonly affects both men and women and is usually seen in teenagers and young adults. While many factors contribute to acne’s severity, one cause is an excess of circulating androgens. 

Spironolactone decreases androgen production of androgen, blocks the androgen’s ability to act on the skin, and reduces acne lesions on the face, neck, and back. Because spironolactone minimizes testosterone (an androgen) in the body, it is typically only used to treat acne vulgaris in women. A typical dose of spironolactone for acne vulgaris in women is 50 to 100 mg once per day. 

Spironolactone dosage for children 

Spironolactone is approved for use in children as young as infants. Here are the typical pediatric doses of spironolactone for each condition. It is typically given as a tablet by mouth. For pediatric use, tablets are often crushed and put into a liquid suspension.

Spironolactone dosage restrictions 

Hepatic and renal impairment

Use spironolactone with caution in patients with liver conditions (hepatic impairment). Doses of spironolactone for patients with renal impairment or renal insufficiency should be modified. In severe renal disease, defined as eGFR <30 in adults or CrCl <10 in children, do not use spironolactone at all. 

Spironolactone can increase adverse effects, cause elevated potassium, or worsen renal disease in individuals with kidney and heart disease. For individuals with mild kidney disease, spironolactone may still be used, just at a lower dose of 12.5 mg every other day. Individuals with severe kidney disease should not take spironolactone.

Testiculotoxicity

Carefully monitor spironolactone use in developing males to avoid adverse effects on the testicles and levels of androgen hormones in the blood. Since spironolactone decreases testosterone production, it can also cause gynecomastia—a condition where males develop breast tissue enlargement and breast tenderness.

Spironolactone dosage for pets 

Spironolactone is a commonly used diuretic in dogs and cats with congestive heart failure or other conditions where the animals retain too much fluid. It may also be combined with furosemide for difficult cases of congestive heart failure or fluid retention due to liver failure. It's dosed at 0.25 to 2 mg/lb (0.5 to 4 mg/kg) one to two times daily for dogs and cats. Specialty pharmacies compound spironolactone for use in pets.

Spironolactone should not be used in animals with kidney dysfunction, elevated serum potassium, Addison’s disease, or pregnant animals. Common side effects of spironolactone in pets include dehydration and electrolyte imbalances. In higher doses, spironolactone can cause loss of appetite, vomiting, or diarrhea.

How to take spironolactone

Spironolactone should be taken by mouth exactly as a healthcare provider prescribes it. Taking it with a meal can aid in absorption and decrease the chance of having an upset stomach. A healthcare provider will monitor kidney and liver function regularly while taking spironolactone. 

• Doses may need to be changed several times to find what works best for a patient.

• Patients may take this medicine with or without food, but it should be taken the same way (with or without food) each day.

• The oral liquid form should be measured with a marked measuring spoon, oral syringe, or medicine cup and shaken well before each use.

• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Spironolactone dosage FAQs

How long does it take spironolactone to work?

For most conditions, spironolactone takes several days to several weeks to start working. For acne vulgaris, this period can be even longer, with most people noticing improvement after several months. 

How long does spironolactone stay in your system?

Spironolactone has a half-life of approximately 90 minutes. While this is relatively short, the metabolites, substances derived from spironolactone, have longer half-lives ranging from three to more than 11 hours. Most drugs are completely eliminated from the body in four to five half-lives, so traces of spironolactone could be found in the body for up to three days.

What happens if I miss a dose of spironolactone?

If the patient misses a maintenance dose of spironolactone, they should take the next dose as soon as they remember. If it is close to the next scheduled dose, take the next scheduled dose and then return to the regular dosing schedule. The doses should not be doubled to “catch up.” 

How do I stop taking spironolactone?

Spironolactone may be stopped at any time. There are no withdrawal symptoms from discontinuing spironolactone, but patients may experience symptoms of the condition it was prescribed to treat. A healthcare provider should be consulted before discontinuing the use of spironolactone. The patient and healthcare provider, as a team, can determine if or when stopping spironolactone is appropriate.

If the patient needs to stop using spironolactone, or if they have advanced kidney or liver disease, a healthcare provider may recommend a different medication. Here are some alternative medications that may be prescribed instead.

* Treatment options depend on the cause of precocious puberty

What is the maximum dosage for spironolactone?

Adults should never take more than 400 mg of spironolactone per day or give more than 100 mg per day to children. Too much spironolactone can cause a drop in blood pressure from sitting to standing (postural hypotension), which can cause dizziness, lightheadedness, or fainting. 

What interacts with spironolactone?

Food-drug interactions

Several clinical studies suggest that taking spironolactone with food increases its absorption and availability, but it does not need to be taken with food to work effectively. Potassium-rich foods (bananas, avocados, coconuts or coconut water, sweet potatoes, etc.) should be eaten in moderation while taking spironolactone. Salt substitutes with potassium should not be taken while taking spironolactone.

Drug-drug interactions

The following drugs should be avoided or taken with caution while using spironolactone:

• Potassium supplements

• Other potassium-sparing diuretics

• Digoxin

• Angiotensin-converting enzyme (ACE) inhibitors

• Certain NSAIDs like indomethacin

• Lithium

• Aldosterone blockers 

• Heparin or low molecular weight heparin

• Amiloride

• Eplerenone

• Isocarboxazid

• Triamterene

• Amikacin

• Clofarabine

• Clonidine

• Guanfacine

• Lofexidine

• Mannitol

• Tacrolimus

Is spironolactone safe for use in pregnant women or while breastfeeding?

Women should speak with their healthcare provider before becoming pregnant, during pregnancy, and while breastfeeding if they are taking spironolactone. Since spironolactone blocks the male hormone testosterone, this may affect the ability of the genitals to form correctly in a male fetus.

While some diuretics have been shown to have a negative effect on breast milk production, it is unlikely that spironolactone alone is potent enough to cause this effect. However, spironolactone can be found in breast milk.

Related resources for spironolactone doses:

• Spironolactone

• Aldactone (spironolactone)

• Spironolactone during breastfeeding

• The effect of spironolactone in patients with severe heart failure

• Spironolactone for drug-resistant hypertension

• Influence of food on the bioavailability of spironolactone

• Study warns of danger of combining spironolactone and ACE inhibitors in heart patients

• Lithium drug interactions

• Spironolactone-induced changes in digoxin kinetics