Spironolactone is used to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. It is also used to treat swelling (edema) caused by certain conditions (e.g., congestive heart failure) by removing excess fluid and improving symptoms such as breathing problems. This medication is also used to treat low potassium levels and conditions in which the body is making too much of a natural chemical (aldosterone). Spironolactone is known as a "water pill" (potassium-sparing diuretic).

Take this medication by mouth, as directed by your doctor. If stomach upset occurs, take it with food or milk. It is best to take your dose early in the day (before 6 p.m.) to prevent having to get up during the night to urinate. Consult your doctor or pharmacist if you have any questions. Dosage is based on your medical condition and response to therapy. In children, the dosage is also based on body weight. Take this medication regularly in order to get the most benefit from it. Remember to use it at the same time(s) each day as directed. It is important to continue taking this medication even if you feel well. Most people with high blood pressure do not feel sick. Take this medication exactly as prescribed. Do not increase your dose, take it more often than prescribed, or stop using this medicine without first consulting your doctor. Your condition may become worse when the drug is suddenly stopped. Inform your doctor if your condition worsens (e.g., if you notice an increase in your routine blood pressure readings).

Before taking spironolactone, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: no urine output (anuria), severe kidney disease, high blood potassium (hyperkalemia). Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver or kidney problems, untreated mineral imbalance (e.g., low sodium). Before having surgery, tell your doctor or dentist that you are taking this medication. This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. This medication passes into breast milk but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first. This drug should not be used with the following medication because very serious interactions may occur: eplerenone. If you are currently using the medication listed above, tell your doctor or pharmacist before starting spironolactone. Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: corticosteroids (e.g., prednisone), certain hormones (ACTH), digoxin, lithium, mitotane, nonsteroidal anti-inflammatory drugs (NSAIDs such as ibuprofen, indomethacin), other diuretics that increase potassium (e.g., amiloride, triamterene). Other medications besides this medication which may increase your potassium levels include cyclosporine, tacrolimus, potassium supplements, ACE inhibitors (e.g., captopril, lisinopril) or ARBs (e.g., losartan, candesartan). Follow your doctor's instructions carefully and continue medications for your condition as directed. Limit foods high in potassium such as bananas, tomatoes, potatoes, low-salt milk, and salt substitutes. Consult your doctor or pharmacist for more details, including diet recommendations. It is important to keep all medical and laboratory appointments so your doctor can monitor your potassium levels regularly. Check the labels on all your medicines (e.g., cough-and-cold products, diet aids, NSAIDs for pain/fever reduction) because they may contain ingredients that could increase your blood pressure or worsen swelling (edema). Some nonprescription medicines that contains aspirin may decrease the effects of spironolactone. Low-dose aspirin, as prescribed by your doctor for specific medical reasons such as heart attack or stroke prevention (usually these dosages are 81-325 milligrams per day) should be continued. Consult your doctor or pharmacist for more details. This medication can affect the results of certain lab tests (e.g., digoxin or cortisol levels). Make sure laboratory personnel and your doctors know you use this drug. This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

Drowsiness, lightheadedness, stomach upset, diarrhea, nausea, vomiting, or headache may occur. To minimize lightheadedness, get up slowly when rising from a seated or lying position. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor immediately if any of these unlikely but serious side effects occur: dizziness, increased thirst, change in the amount of urine, mental/mood changes, unusual fatigue/weakness, muscle spasms, menstrual period changes, breast enlargement (gynecomastia) in men, sexual function problems. This medication may lead to high levels of potassium, especially in patients with kidney problems. If not treated, very high potassium levels can be fatal. Tell your doctor immediately if you notice any of the following unlikely but serious side effects: slow/irregular heartbeat, muscle weakness. Tell your doctor immediately if any of these rare but very serious side effects occur: signs of infection (e.g., fever, persistent sore throat), severe stomach/abdominal pain, persistent nausea/vomiting, vomit that looks like coffee grounds, dark urine, yellowing of the eyes/skin. A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Store the US product at room temperature below 77 degrees F (25 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.