Medications and Drugs
Medical Author: Omudhome Ogbru, Pharm.D.
Medical Editor: Jay Marks, M.D.
GENERIC NAME: spironolactone
BRAND NAME: Aldactone
DRUG CLASS AND MECHANISM: One of the main functions of the kidneys is
to retain salt (sodium chloride) and water in the body. In patients with heart
failure and cirrhosis, increased levels of a hormone produced by the adrenal
glands, called aldosterone, causes salt and fluid to be retained by the kidneys.
(At the same time, it also causes the kidneys to eliminate potassium.) The body
becomes overloaded with salt and water, and this worsens the heart failure.
Spironolactone inhibits the action of aldosterone thereby causing the kidneys to
excrete salt and fluid in the urine while retaining potassium. Therefore,
spironolactone is classified as a potassium-sparing diuretic, a drug that
promotes the output of urine (diuretic) while allowing the kidneys to hold onto
potassium. The FDA approved spironolactone in October 1985.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes
PREPARATIONS: Tablets 25, 50, and 100 mg
STORAGE: Spironolactone should be stored at room temperature, below
25 C (77 F).
PRESCRIBED FOR: Spironolactone removes excess fluid from the body in
congestive heart failure, cirrhosis of the liver, and kidney disease. It can
also be used in combination with other drugs to treat
elevated blood pressure
and for treating diuretic-induced low potassium (hypokalemia). Spironolactone
also is used to counteract the effects of excessive adrenal aldosterone
production (hyperaldosteronism). Aldosterone overproduction can occur from a
tumor in the adrenal gland or enlarged adrenal glands (hyperplasia of the
adrenal glands).
DOSING: Spironolactone may be taken with or without food. The dosage
range is 25-400 mg daily in single or divided doses.
DRUG INTERACTIONS: Spironolactone can lower blood sodium levels while
raising blood potassium levels. Excessively high blood potassium levels can lead
to potentially life-threatening abnormalities in the
rhythm of the heart.
Therefore, spironolactone usually is not administered with other agents that can
raise blood potassium levels, such as potassium supplements,
angiotensin
converting enzyme (ACE) inhibitors [for example, enalapril
(Vasotec)], indomethacin
(Indocin), or other potassium-sparing diuretics. Spironolactone can cause
elevation of blood digoxin (Lanoxin) to toxic levels, requiring adjustment of
the digoxin dosage.
PREGNANCY: There are no adequate studies in
pregnant women.
Spironolactone may be harmful if used for treating gestational hypertension
(high blood pressure during pregnancy).
NURSING MOTHERS: An active metabolite of spironolactone is secreted in
breast-milk. To avoid adverse effects in the newborn, mothers should avoid
breastfeeding while taking spironolactone.
SIDE EFFECTS: Side effects of spironolactone include headache,
diarrhea, cramps, drowsiness, rash, nausea,
vomiting, impotence,
irregular
menstrual periods, and irregular hair growth. Fluid and electrolytes imbalance
(for example, low sodium, low magnesium, and
high potassium) may
occur, so patients should be monitored carefully. Enlargement of the breasts
(gynecomastia) may also occur and is related to dose and duration of therapy. It
usually reverses upon discontinuation of spironolactone.
Reference: FDA Prescribing Information
Last Editorial Review: 12/17/2008
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
- Congestive Heart Failure - Read about congestive heart failure symptoms like fatigue, abdomen, leg and ankle swelling, shortness of breath, sleeplessness, increased urination, nausea, abdominal pain, and decreased appetite.
- Drugs: What You Should Know About Your Drugs - Find out what you should know about your drugs such as side effects, warnings and precautions, storage information, and if a generic version is as good as the brand name.
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