Products
Spironolactone is commercially available in film-coated tablet form as a monopreparation (Aldactone) and in fixed combination with furosemide (Furospir). It was developed in the 1950s at G.D. Searle in Chicago and approved in 1959, and in many countries in 1961.
Structure and properties
Spironolactone (C24H32O4S, Mr = 416.6 g/mol) exists as a white to yellowish white powder that is practically insoluble in water. It was structurally derived from aldosterone. Active metabolites such as canrenone are involved in the effect. Drospirenone (Yasmin) was developed starting from spironolactone.
Effects
Spironolactone (ATC C03DA01) has weak diuretic, antihypertensive, and additional antiandrogenic properties. It leads to increased excretion of water and sodium and retains potassium in the body. The diuretic and antihypertensive effects are due to antagonism at the intracellular aldosterone receptor on the late distal tubule and collecting tube of the nephron of the kidney. This inhibits protein synthesis promoted by aldosterone. The effect is delayed, occurring after two to three days, and persists for about three days after the end of therapy. Spironolactone itself has a short half-life of one to two hours. However, those of the active metabolites are up to 20 hours. Therefore, once-daily administration is possible.
Indications
- Essential hypertension (high blood pressure).
- Hypertension associated with increased aldosterone secretion, hypokalemia, and metabolic alkalosis.
- Edema in heart failure
- Liver cirrhosis with ascites
- Nephrotic syndrome
- Edema associated with secondary aldosteronism.
- Diagnosis and treatment of primary hyperaldosteronism.
Spironolactone is also used as an antiandrogen, especially in the United States, for example in acne, hirsutism, and hereditary hair loss. Topical medicines are also available in some countries.
Dosage
According to the professional information. Tablets are usually taken once or twice daily.
Abuse
Spironolactone can be abused as a doping agent (diuretic and masking agent) and is prohibited in professional sports both during and outside of athletic competition.
Contraindications
- Hypersensitivity
- Acute renal failure, severe renal insufficiency, anuria.
- Addison’s disease
- Hyperkalemia
- Hyponatremia
- Concurrent administration of eplerenone.
- Pregnancy and lactation
Full precautions can be found in the drug label.
Interactions
Spironolactone has a relatively high potential for interaction with various substances. Simultaneously administered agents that increase potassium levels may cause dangerous hyperkalemia. Renal failure may occur when combined with ACE inhibitors and furosemide. NSAIDs may attenuate the diuretic effect and increase the risk for hyperkalemia.
Adverse effects
The most common possible adverse effects include hyperkalemia, cardiac arrhythmias, and gynecomastia, which is an enlargement of the mammary gland in men. Other possible side effects include:
- Headache, drowsiness, confusion, gait disturbances, dizziness.
- Gastrointestinal disorders
- Skin rashes, increased hair growth or hair loss.
- Men: impotence disorders, erectile dysfunction, impotence, reduction in motility and sperm count.
- Women: Irregular menstrual periods, absence of bleeding, bleeding after menopause, breast pain, libido changes.
