Oral Spironolactone — Important Safety Information

What is oral spironolactone?

Spironolactone is a prescription tablet that belongs to a class of medications called aldosterone antagonists — a type of potassium-sparing diuretic (water pill). It also blocks androgen receptors, which is why clinicians prescribe it off-label for hormonal acne and for unwanted facial and body hair growth in women. Because it acts as a mild diuretic, it can affect your fluid balance, blood pressure, and potassium level in addition to your skin.

Who should not take it?

• Anyone who is pregnant or trying to become pregnant. Spironolactone may affect the sexual development of a male fetus and should be avoided during pregnancy.
• Anyone with a high blood potassium level (hyperkalemia).
• Anyone with Addison's disease.
• Anyone taking eplerenone.
• Anyone with a known allergy to spironolactone.
• People with significant kidney impairment, liver disease, or heart failure should generally avoid it for cosmetic or dermatologic use; discuss your full history with your provider.

Tell your provider about these medications

Several medications raise potassium and can add to spironolactone's effect. Tell your provider if you take any of the following:

• ACE inhibitors (such as lisinopril) or ARBs (such as losartan), or any other blood pressure medication.
• Potassium supplements, potassium-containing salt substitutes, or high-dose electrolyte powders.
• Trimethoprim/sulfamethoxazole (Bactrim) or other antibiotics.
• Regular or high-dose NSAIDs such as ibuprofen or naproxen.
• Lithium — spironolactone can raise lithium levels.
• Digoxin — spironolactone can affect both digoxin levels and the accuracy of digoxin blood tests.
• Drospirenone-containing birth control pills (such as Yaz, Yasmin, or Slynd), which also have a potassium-sparing effect.

Pregnancy and contraception

Do not take spironolactone if you are pregnant or may become pregnant. Because of the potential risk to a male fetus, clinicians generally recommend reliable contraception while on treatment. Tell your provider right away if you become pregnant or plan to. Only limited information is available on use while breastfeeding; discuss it with your provider before continuing.

How should I take it?

Take your tablet by mouth once daily, at about the same time each day, exactly as prescribed. Taking it in the morning can reduce nighttime trips to the bathroom. Do not take more than prescribed, and do not add potassium supplements or potassium-based salt substitutes without checking first. Improvement in acne is gradual and builds over several months of consistent daily use — your clinician will reassess your response and may adjust your dose. If treatment stops, hormonal acne commonly returns.

Potassium and blood tests

Spironolactone causes the body to hold on to potassium. In healthy young women with normal kidney function, clinically significant increases are uncommon, and current dermatology guidance does not call for routine potassium monitoring in that group. Your provider may order blood work before or during treatment if you are older, take an interacting medication, or have kidney, liver, heart, or adrenal conditions, or diabetes. Report muscle weakness, numbness or tingling, an unusually slow or irregular heartbeat, or unexplained fatigue promptly — these can be signs of a high potassium level.

What should I tell my EOS Health-affiliated provider?

Share every medication and supplement you take and your full medical history — especially kidney, liver, heart, or adrenal conditions, diabetes, high or low blood pressure, a history of high potassium, irregular menstrual cycles, breast lumps or breast cancer, and any current or planned pregnancy.

Most serious side effects

If experiencing a medical emergency, call 911.

• Signs of a high potassium level: muscle weakness, numbness or tingling, confusion, a slow or irregular heartbeat, or fainting.
• Serious allergic reactions: rash, hives, swelling of the lips, tongue, or face, or trouble breathing.
• Signs of dehydration or low blood pressure: severe dizziness, fainting, or a marked decrease in urination.
• Signs of a liver problem: yellowing of the skin or eyes, dark urine, or severe abdominal pain.
• A new breast lump, breast pain, or nipple discharge.
• A severe or blistering skin rash.

Most common side effects

• Increased urination, especially in the first few weeks.
• Irregular or missed periods, or spotting between periods — more likely at higher doses and less common when taken with a combined oral contraceptive.
• Breast tenderness or enlargement.
• Lightheadedness, dizziness on standing, or fatigue.
• Headache.
• Increased thirst, or a mild decrease in blood pressure.

Most of these effects are dose-related and often ease as your body adjusts. Tell your provider if any of them persist or interfere with daily life — a dose adjustment often helps.

A note on animal studies

High doses of spironolactone were associated with tumors in long-term rat studies, which is reflected in the nonclinical section of the prescribing information. Large human studies have not shown an increased risk of breast cancer with spironolactone use. Discuss any personal or family history of breast cancer with your provider.

You are encouraged to report negative side effects to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.

This information is not comprehensive. Please reach out to your EOS Health-affiliated provider with any questions or concerns.