Aldactone (spironolactone) Side Effects, Interactions, and Warnings

Aldactone (spironolactone) is a potassium-sparing diuretic that removes excess fluid from the body in congestive heart failure, cirrhosis of the liver, and kidney disease. It also can be used in combination with other drugs to treat diuretic-induced low potassium (hypokalemia) and high blood pressure (hypertension). Aldactone also is used to counteract the effects of excessive adrenal aldosterone production (hyperaldosteronism) that can occur from a tumor in the adrenal gland or enlarged adrenal glands (hyperplasia of the adrenal glands). Common side effects of Aldactone include headache, diarrhea, cramps, drowsiness, rash, nausea, vomiting, impotence, irregular menstrual periods, irregular hair growth, and enlargement of male breasts (usually reverses on discontinuation of Aldactone).

Serious side effects of Aldactone include

• liver dysfunction,
• kidney failure,
• severe allergic reaction (anaphylaxis),
• abnormal heart rhythm,
• low platelets,
• low white blood cells,
• toxic epidermal necrolysis,
• vasculitis,
• risk of tumors in animal studies, and
• fluid and electrolyte imbalances.

Drug interactions of Aldactone include potassium supplements, angiotensin converting enzyme (ACE) inhibitors, indomethacin, other potassium-sparing diuretics, and digoxin. There are no adequate studies in pregnant women. Aldactone may be harmful if used for treating gestational hypertension (high blood pressure during pregnancy). An active metabolite of Aldactone is secreted in breast milk. To avoid adverse effects in the newborn, mothers should avoid breastfeeding while taking Aldactone.

Common side effects of Aldactone include:

• Headache
• Diarrhea
• Cramps
• Drowsiness
• Rash
• Nausea
• Vomiting
• Impotence
• Irregular menstrual periods
• Irregular hair growth

Enlargement of the male breasts (gynecomastia) may also occur and is related to dose and duration of therapy. It usually reverses upon discontinuation of Aldactone.

Possible serious side effects of Aldactone include:

• Liver dysfunction
• Kidney failure
• Anaphylaxis
• Abnormal heart rhythm
• Low platelets
• Low white blood cells
• Toxic epidermal necrolysis
• Vasculitis
• Risk of tumors in animal studies

Fluid and electrolytes imbalance (for example, low sodium, low magnesium, and high potassium) may occur, so patients should be monitored carefully.

The following adverse reactions have been reported and, within each category (body system), are listed in order of decreasing severity.

Digestive: Gastric bleeding, ulceration, gastritis, diarrhea and cramping, nausea, vomiting.

Reproductive: Gynecomastia, inability to achieve or maintain erection, irregular menses or amenorrhea, postmenopausal bleeding, breast pain. Carcinoma of the breast has been reported in patients taking ALDACTONE but a cause and effect relationship has not been established.

Hematologic: Leukopenia (including agranulocytosis), thrombocytopenia.

Hypersensitivity: Fever, urticaria, maculopapular or erythematous cutaneous eruptions, anaphylactic reactions, vasculitis.

Metabolism: Hyperkalemia, electrolyte disturbances.

Musculoskeletal: Leg cramps.

Nervous system /psychiatric: Lethargy, mental confusion, ataxia, dizziness, headache, drowsiness.

Liver / biliary: A very few cases of mixed cholestatic/hepatocellular toxicity, with one reported fatality, have been reported with ALDACTONE administration.

Renal: Renal dysfunction (including renal failure).

Skin: Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms (DRESS), alopecia, pruritis.

ACE Inhibitors

Concomitant administration of ACE inhibitors with potassium-sparing diuretics has been associated with severe hyperkalemia.

Angiotensin II Antagonists, Aldosterone Blockers, Heparin, Low Molecular Weight Heparin, And Other Drugs Known To Cause Hyperkalemia

Concomitant administration may lead to severe hyperkalemia.

Alcohol, Barbiturates, or Narcotics

Potentiation of orthostatic hypotension may occur.

Corticosteroids, ACTH

Intensified electrolyte depletion, particularly hypokalemia, may occur.

Pressor Amines (e.g., norepinephrine)

ALDACTONE reduces the vascular responsiveness to norepinephrine. Therefore, caution should be exercised in the management of patients subjected to regional or general anesthesia while they are being treated with ALDACTONE.

Skeletal Muscle Relaxants, Nondepolarizing (e.g., tubocurarine)

Possible increased responsiveness to the muscle relaxant may result.

Lithium

Lithium generally should not be given with diuretics. Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity.

Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

In some patients, the administration of an NSAID can reduce the diuretic, natriuretic, and antihypertensive effect of loop, potassium-sparing, and thiazide diuretics. Combination of NSAIDs, e.g., indomethacin, with potassium-sparing diuretics has been associated with severe hyperkalemia. Therefore, when ALDACTONE and NSAIDs are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained.

Digoxin

ALDACTONE has been shown to increase the half-life of digoxin. This may result in increased serum digoxin levels and subsequent digitalis toxicity. It may be necessary to reduce the maintenance and digitalization doses when ALDACTONE is administered, and the patient should be carefully monitored to avoid over- or under-digitalization.

Cholestyramine

Hyperkalemic metabolic acidosis has been reported in patients given ALDACTONE concurrently with cholestyramine.

Drug/Laboratory Test Interactions

Several reports of possible interference with digoxin radioimmunoassay by ALDACTONE, or its metabolites, have appeared in the literature. Neither the extent nor the potential clinical significance of its interference (which may be assay-specific) has been fully established.