Generic Name: Spironolactone
Product Name: Spiractin
This drug may be used in the treatment of essential hypertension (high blood pressure) to lower systolic and diastolic blood pressure. It can be used alone or in conjunction with other therapies such as thiazide diuretics or other antihypertensives such as beta-blockers.
- Spironolactone may also be used alone or in conjunction with other diuretics for the treatment of congestive heart failure for managing oedema (swelling due to fluid retention) and sodium retention
- It may also be used for the treatment of ascities (abdominal swelling due to fluid retention) and oedema due to hepatic cirrhosis
- This drug can also be used for the treatment of malignant hypertension, nephrotic syndrome, primary hyperaldosteronism, diuretic induced hypokalaemia (insufficient potassium) and hirsutism (excessive hair) in females.
- Spironolactone is an aldosterone antagonist (aldosterone is an endogenous hormone responsible for salt and water balance in the kidney).
- It competitively binds receptors at the aldosterone dependent sodium-potassium exchange site in the distal convoluted tubule of the nephron (the functional unit of the kidney) leading to an increased amount of sodium and water excretion in the urine, whilst retaining potassium.
- Spironolactone also has moderate antiandrogenic effects by inhibiting the interaction between dihydrotestosterone and the intracellular androgen receptor- this may lower plasma levels of testosterone and therefore be beneficial in the treatment of hirsutism.
- Usual dosage is 50-100mg/day either in a single dose or as divided doses.
- Initial dosage is 100mg/day.
- This may be increased up to 200mg/day depending on clinical scenario.
- Recommended dosing ranges from 100-400mg/day depending on the urinary sodium:potassium ratio.
- Usual dose is 100-200mg/day
- Initial daily dosage should be approximately 3.3mg/kg of bodyweight
- Spironolactone may be used to aid the diagnosis of primary hyperaldosteronism; 400mg of this drug should be administered daily for three to four weeks. Correction of hypokalaemia and hypertension presumes a diagnosis of primary hyperaldosteronism. Alternatively, 400mg may be administered for 4 days – if serum potassium increases whilst using Spironolactone but drops when it is discontinued, this is also suggestive of primary hyperaldosteronism. More definitive tests should be undertaken following this regime.
- Spironolactone may also be used for long term maintenance therapy of primary hyperaldosteronism in patients unsuitable for surgery – this involves using this therapy at the lowest effective dose
- Spironolactone is always used as adjunctive therapy in this scenario.
- Initial dose is 100mg/day, increased if necessary at two week intervals to 400mg/day.
- Dosing should begin at low levels and then increase if appropriate
- Dosage in this situation should not exceed more than 100mg/day
- Usual dose is 100-200mg/day according to patient response. 50mg daily may be sufficient in some cases.
- Therapy may be given by cyclical dosing every three weeks out of four or continuous administration.
Common side effects
- gynaecomastia (normally reversible)
- gastrointestinal disturbances: nausea, vomiting, diarrhoea, cramping
- menstrual irregularities
Uncommon side effects
- skin reactions
- drug fever
- benign breast disorders
- irregular muscular coordination
For further information talk to your doctor.