Spironolactone

Spironolactone is a potassium-sparing diuretic (water pill) used for heart failure, high blood pressure, fluid build-up (edema) caused by liver or kidney disease, and a hormone condition called primary hyperaldosteronism. Spironolactone is sometimes prescribed off-label for women with acne or excessive facial hair growth (hirsutism).

Spironolactone works by blocking a hormone called aldosterone, which causes your body to pass more salt and water in your urine while keeping potassium in. This is why it is called potassium-sparing, and it is what makes spironolactone different from most other water pills, which flush potassium out.

Spironolactone also blocks androgens such as testosterone from binding to the androgen receptor, which explains several of its side effects, including breast tenderness and breast growth.

Spironolactone is FDA-approved to treat adults with:

• Heart failure (NYHA Class III-IV) with a reduced ejection fraction to help live longer, reduce swelling, and reduce the need for hospital stays. It is taken alongside other heart failure medicines rather than on its own.
• High blood pressure as an add-on treatment for people whose blood pressure is not controlled well enough by other medicines. Lowering blood pressure reduces the risk of stroke and heart attack.
• Fluid build-up (edema) caused by cirrhosis of the liver when cutting back on fluid and salt has not been enough, and also for swelling caused by nephrotic syndrome (a kidney disorder) when treating the underlying disease and using other water pills have not worked well enough.
• Primary hyperaldosteronism, which is a condition where the adrenal glands make too much aldosterone. Spironolactone is used short-term to prepare for surgery, and long-term for people who are not suitable for surgery.

Spironolactone tablets come in 25 mg, 50 mg, and 100 mg strengths. Spironolactone 25 mg is the strength most often used to start treatment. There is also a banana-flavored oral liquid for people who cannot swallow tablets. The liquid and the tablets are not interchangeable, so never switch between them without your doctor changing your dose.

Take spironolactone exactly as prescribed. Follow all directions on your prescription label and read all medication guides.

• Take it the same way each day, either always with food or always without. Food increases how much spironolactone your body absorbs, roughly doubling it, so switching back and forth changes how much medicine you actually get.
• Shake the oral liquid well before every dose, and measure it with the marked oral syringe, dosing spoon, or medicine cup that comes with it, not a kitchen spoon.
• Do not switch between tablets and the oral liquid without your doctor changing the dose. They are not interchangeable, and the liquid gives a higher level of medicine in your blood for the same number of milligrams.
• You will need regular blood tests to check your potassium, sodium, kidney function, uric acid, and blood sugar. Keep these appointments even if you feel completely well.
• If you are being treated for high blood pressure, keep taking spironolactone even when you feel fine. High blood pressure usually has no symptoms.
• Tell any doctor or dentist treating you that you take spironolactone, and tell your surgeon before any operation.
• Spironolactone can interfere with one type of blood test used to measure digoxin, so mention it if you take digoxin.
• Do not share this medicine with anyone else.
• Store tablets at room temperature, 68°F to 77°F (20°C to 25°C), and protect them from light. Store the oral liquid at room temperature and keep it in a tightly closed bottle.

Do not take spironolactone if you have a high potassium level in your blood, if you have Addison's disease (an adrenal gland disorder), or if you are taking eplerenone (Inspra), another medicine of the same type.

Spironolactone can raise your potassium to a dangerous level. A high potassium level can cause a life-threatening change in your heart rhythm, and it often causes no symptoms until it is already high. Your doctor should check your potassium with a blood test within a week of you starting spironolactone or having your dose changed, and regularly after that.

Your risk of high potassium is greater if your kidneys do not work well, if you take potassium supplements or a salt substitute containing potassium, or if you take an ACE inhibitor, an ARB, an NSAID, heparin, or trimethoprim.

Do not use potassium supplements or salt substitutes containing potassium unless your doctor has specifically told you to.

Passing too much fluid can drop your blood pressure and make your kidney function worse, especially if you are also taking an ACE inhibitor or an ARB. Tell your doctor if you feel faint, or if you become unwell with vomiting or diarrhea.

If you have cirrhosis with fluid in your abdomen, spironolactone is usually started in hospital, because sudden shifts in fluid and salt can affect how your brain works.

Spironolactone should be avoided in pregnancy where possible, because it blocks male hormones and may affect how a male baby develops.

You should not use spironolactone if you are allergic to it, or if you have:

• a high level of potassium in your blood (hyperkalemia);
• Addison's disease (an adrenal gland disorder); or
• if you are taking eplerenone.

To make sure spironolactone is safe for you, tell your doctor if you have or have ever had:

• kidney disease, or reduced kidney function;
• liver disease, especially cirrhosis or fluid in the abdomen (ascites);
• an electrolyte imbalance, such as a low sodium, magnesium, or calcium level;
• dehydration, or any illness causing vomiting or diarrhea;
• diabetes, since spironolactone can raise blood sugar;
• gout or a high uric acid level; or
• prostate cancer treated with abiraterone.

Pregnancy

Spironolactone blocks the effect of male hormones, and male hormones are needed for a male baby to develop normally. In animal studies, male offspring exposed in the womb showed feminized development. The limited information available in humans has not shown a clear increase in birth defects, but the concern remains. Your doctor will usually avoid spironolactone in pregnancy, or talk through the possible risk to a male baby with you. Untreated heart failure, cirrhosis, and high blood pressure also carry real risks in pregnancy, so this is a decision to make with your doctor rather than by stopping on your own.

Breastfeeding

Spironolactone itself does not pass into breast milk. Its active breakdown product, canrenone, has been found in breast milk in very small amounts that are not expected to affect a breastfed baby. No side effects were reported in the one infant studied over a short period, and the long-term picture is not known. Talk to your doctor so you can weigh this up together.

Children

Spironolactone has not been shown to be safe and effective in children. The oral liquid is specifically not recommended for treating high blood pressure in children, because of the hormonal effects of the medicine. Any use in a child must be decided and monitored by a specialist.

Older adults

Spironolactone is cleared by the kidneys, and kidney function tends to fall with age. Older adults are therefore more likely to build up a high potassium level, so kidney function and potassium need monitoring.

Reported spironolactone side effects

Reported spironolactone side effects include breast and nipple pain in both men and women, a lower sex drive, trouble getting or keeping an erection, irregular or missed periods, bleeding after menopause, dizziness, headache, drowsiness, feeling sluggish, leg cramps, nausea, vomiting, diarrhea, stomach cramps, indigestion, hair thinning, and itching.

The most common side effect of spironolactone is breast growth in men, known as gynecomastia. In the main heart failure study, about 9 in 100 men taking an average of 26 mg a day developed it. The chance goes up on higher doses. It can start anywhere from one or two months into treatment to more than a year later, and it usually goes away after the medicine is stopped.

Several of these effects are dose-related, so they are more likely on higher doses, and many settle after the dose is lowered or the medicine is stopped. How often most of them happen is not known, because they come from reports gathered after the medicine was approved rather than from counted numbers in trials.

Serious spironolactone side effects

Get emergency medical help if you have signs of an allergic reaction to spironolactone: hives, difficulty breathing, or swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• signs of a high potassium level (hyperkalemia), such as muscle weakness or a heavy feeling in your legs, a slow or uneven heartbeat, numbness or tingling in your hands, feet, or lips, nausea, or feeling restless and on edge;
• a light-headed feeling like you might pass out, which can be a sign you have low blood pressure (hypotension)
• little or no urination, or swelling in your ankles, hands, or feet, which can be signs your kidneys are struggling (worsening renal function);
• signs of a low sodium level, such as confusion, severe weakness, muscle pain or cramps, feeling unsteady, or slurred speech;
• severe or ongoing vomiting or diarrhea, since losing too much fluid and salt can send your blood pressure and kidney function the wrong way;
• a skin rash that spreads or blisters, peeling skin, sores in your mouth, or a rash with a fever and swollen glands, which can be signs of a rare but serious skin reaction;
• yellowing of your eyes or skin, dark urine, or pain in your upper stomach, which can be signs of a liver problem;
• a fever, sore throat, or unusual bruising or bleeding, which can be signs of a problem with your blood cells; or
• new confusion, unsteadiness, or extreme drowsiness if you have liver disease, since spironolactone can make brain function worse in people with cirrhosis.

Spironolactone side effects in men

Men are most likely to notice effects linked to spironolactone blocking male hormones. These include breast growth and breast tenderness, a lower sex drive, and difficulty getting or keeping an erection. Breast growth is dose related, so tell your doctor early rather than waiting, since a lower dose or a different medicine may be an option.

Spironolactone side effects in women

Women may notice irregular periods, missed periods, breast tenderness, or bleeding after menopause. Some women also notice patchy darkening of the skin on the face. Report any unexpected bleeding after menopause to your doctor so it can be checked properly rather than assumed to be a side effect.

Long-term spironolactone side effects

The main long-term concerns with spironolactone are chemical rather than something you would feel. Over time it can push your potassium too high, and it can also lower your sodium, magnesium, and calcium, raise your blood sugar, and raise your uric acid, which occasionally brings on gout. This is why you need regular blood tests for as long as you take it, not just at the start.

In animal studies, spironolactone given at high doses over long periods caused tumors in rats, mainly in hormone-producing glands and the liver. No increase in tumors was seen at the lower doses tested, which were still around five times the highest recommended human dose when adjusted for body size. Whether this happens in people is not known.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

The usual starting dose of spironolactone tablets for adults is 25 mg to 100 mg a day, depending on the condition being treated. Your doctor will pick a starting dose and then adjust it based on your blood tests and how you respond.

Spironolactone dosage for heart failure

Treatment starts at spironolactone 25 mg once a day, provided your potassium level is 5.0 mEq/L or lower and your kidney function (eGFR) is above 50. If you tolerate that, the dose may go up to 50 mg once a day. If your potassium rises too high, the dose may drop to 25 mg every other day. If your eGFR is between 30 and 50, your doctor may start you at 25 mg every other day because of the higher risk of high potassium.

Spironolactone dosage for high blood pressure

The usual starting dose is spironolactone 25 mg to 100 mg a day, taken as one dose or split into two. The dose can be adjusted every two weeks. Doses above 100 mg a day do not generally lower blood pressure any further.

Spironolactone dosage for fluid build-up (edema)

The usual starting dose is 100 mg a day, taken as one dose or split into two, and the dose can range from 25 mg to 200 mg a day. If you have cirrhosis, treatment is started in hospital and increased slowly. When spironolactone is the only water pill being used, it is given for at least five days before the dose is increased.

Spironolactone dosage for primary hyperaldosteronism

The dose is 100 mg to 400 mg a day when preparing for surgery. For people who are not suitable for surgery, the lowest dose that works is used long term.

Spironolactone oral liquid doses

The oral liquid has its own separate doses because it is absorbed differently. Heart failure starts at 20 mg (4 mL) once a day. High blood pressure starts at 20 mg (4 mL) to 75 mg (15 mL) a day. Swelling from cirrhosis starts at 75 mg (15 mL) a day, begun in hospital. If more than 100 mg a day is needed, a different form of the medicine should be used instead.

Spironolactone formulations

• Spironolactone 25 mg tablets
• Spironolactone 50 mg tablets
• Spironolactone 100 mg tablets
• Spironolactone oral suspension 25 mg per 5 mL

Take the missed dose as soon as you remember. Skip it if it is almost time for your next dose. Do not take two doses at once to make up for a missed one.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Taking too much spironolactone can cause drowsiness, confusion, a rash, nausea, vomiting, dizziness, or diarrhea. A dangerously high potassium level is the main serious risk, particularly if your kidneys do not work well.

• Avoid potassium supplements, salt substitutes containing potassium, and low-sodium products that use potassium instead of salt. Check labels, since potassium chloride is a common salt replacement.
• Go easy on foods very high in potassium if your doctor has told you to. This is worth asking about specifically, because most people are told to eat more potassium, not less.
• Be careful with NSAIDs such as ibuprofen and naproxen. They can push your potassium up, make spironolactone work less well, and strain your kidneys.
• Limit alcohol. It can add to the dizziness and light-headedness, especially when you first start.
• Avoid getting up quickly from sitting or lying down, and avoid driving or anything hazardous until you know how spironolactone affects you.
• Do not take another medicine containing spironolactone at the same time, such as Aldactazide, and do not take eplerenone.

The most important interactions with spironolactone are medicines that also raise potassium, because the combined effect can push your level dangerously high. Tell your doctor about every medicine you take, including anything you start or stop during treatment. Be especially careful with:

• eplerenone, which should not be taken with spironolactone at all;
• medicines that raise potassium, including ACE inhibitors such as lisinopril and ramipril, ARBs such as losartan and valsartan, NSAIDs, heparin and low molecular weight heparin, and trimethoprim;
• potassium supplements and potassium-containing salt substitutes, which are usually stopped when spironolactone is started for heart failure;
• lithium, since spironolactone slows how fast your kidneys clear it and can cause lithium toxicity, so lithium levels need monitoring;
• digoxin, which needs care for two separate reasons: spironolactone interferes with one type of blood test used to measure digoxin, and it can also raise the actual amount of digoxin in your body;
• NSAIDs, which can also make spironolactone less effective as a water pill and as a blood pressure medicine;
• aspirin, which can reduce how well spironolactone works, so your dose may need adjusting;
• cholestyramine, which together with spironolactone has caused a high potassium level with too much acid in the blood;
• abiraterone, used in prostate cancer, which should not be combined with spironolactone because spironolactone attaches to the androgen receptor and can raise PSA readings;
• mitotane, which should be avoided because spironolactone lowers its level in the blood; and
• other blood pressure medicines and water pills, which add to the blood pressure lowering effect.

This list is not complete. Other prescription and over-the-counter medicines, vitamins, and herbal products can interact with spironolactone. Give a list of all your medicines to any healthcare provider who treats you.