Do NOT use Aldactone if:

• you are allergic to any ingredient in Aldactone
• you are unable to urinate, have severe kidney problems, or have high blood potassium levels
• you are taking a potassium supplement, another potassium-sparing diuretic (eg, amiloride, triamterene), or another aldosterone-blocker (eg, eplerenone).

Contact your doctor or health care provider right away if any of these apply to you.

Some medical conditions may interact with Aldactone. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have high acidity in your body fluids; low blood sodium levels; high blood potassium levels; kidney, liver, or heart disease; diabetes; or high urea or nitrogen in your blood
• if you have menstrual disease.

Some medicines may interact with Aldactone. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Adrenocorticotropic hormone (corticotropin) (ACTH) or corticosteroids (eg, prednisone) or because low blood electrolyte levels may occur
• Barbiturates (eg, phenobarbital) or narcotics (eg, morphine) because dizziness upon standing may occur
• Angiotensin-converting enzyme (ACE) inhibitors (eg, enalapril), angiotensin II receptor antagonists (eg, valsartan), cyclosporine, macrolide immunosuppressives (eg, tacrolimus), other aldosterone-blockers (eg, eplerenone), other potassium sparing diuretics (eg, amiloride, triamterene), or potassium supplements because high blood potassium levels may occur (eg, listlessness, confusion, abnormal skin sensations of the arms and legs, heaviness of limbs, slowed heart rate, irregular heart rhythm, potentially life-threatening slow or irregular heartbeat)
• Nonsteroidal anti-inflammatory drugs (NSAIDs) (eg, indomethacin) because they may decrease Aldactone's effectiveness and increase the risk of kidney problems and high blood potassium
• Digoxin, digitoxin, lithium, nondepolarizing muscle relaxants (eg, tubocurarine), or quinidine because the risk of their side effects and toxicity may be increased by Aldactone
• Pressor amines (eg, norepinephrine) because their effectiveness may be decreased by Aldactone.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Aldactone may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

Important safety information:

• Aldactone may cause dizziness or drowsiness. These effects may be worse if you take it with alcohol or certain medicines. Use Aldactone with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
• Aldactone can raise your body's potassium levels. This is more likely to occur in people with kidney problems or diabetes, in the elderly, or if the patient is severely ill. Potassium levels must be closely monitored in people with any of these problems or illnesses. If not treated, high potassium levels can be fatal.
• Check with your doctor before you use a salt substitute or a product that has potassium in it.
• Lab tests, including kidney function, blood pressure, blood potassium, and chemistries, may be performed while you use Aldactone. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
• Use Aldactone with caution in the elderly; they may be more sensitive to its effects.
• Aldactone should be used with extreme caution in children; safety and effectiveness in children have not been confirmed.
• Pregnancy and breast-feeding: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Aldactone while you are pregnant. Aldactone is found in breast milk. Do not breast-feed while taking Aldactone.

All medicines may cause side effects, but many people have no, or minor, side effects.

Check with your doctor if any of these most common side effects persist or become bothersome:

Diarrhea; drowsiness; headache; nausea; stomach cramping; vomiting.

Seek medical attention right away if any of these severe side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); black, tarry, or bloody stools; change in the amount of urine produced; confusion; dark urine; decreased sexual ability; enlarged breasts in men; irregular or missed menstrual periods; pale stools; severe or persistent stomach pain; symptoms of abnormal fluid or electrolyte levels (eg, fast, slow, or irregular heartbeat; increased thirst; muscle weakness; severe or persistent dry mouth, nausea, or vomiting; severe or persistent dizziness or drowsiness; unusual fatigue or sluggishness; tingling sensation); yellowing of the skin or eyes.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.