Home » Diuretics » Aldactone
Generic name: Spironolactone
Brand names: Aldactone
How does it work?
Aldactone tablets contain the active ingredient spironolactone, which is a type of medicine called a potassium-sparing diuretic. Diuretics are sometimes referred to as '‘water table'ts’. (NB. Spironolactone is also available without a brand name, ie as the generic medicine.)
Spironolactone works by blocking the actions of a hormone in the body called aldosterone. This hormone is produced by glands found above the kidneys called the adrenal glands. Aldosterone acts in the kidneys, where it is involved in controlling the balance of salt and water in the body.
Blocking the action of aldosterone causes the kidneys to increase the amount of salts such as sodium that they filter out of the blood and into the urine. When these salts are filtered out of the blood by the kidneys, water is also drawn alongside. Spironolactone therefore increases the amount of water that is drawn out of the blood and into the urine. This helps excess fluid to be removed from the body.
There are many conditions that can lead to an accumulation of fluid in the body (oedema). These include heart failure (where the fluid may build up in the lungs, causing breathlessness, or the ankles, causing swollen ankles), liver cirrhosis (where fluid may build up in the abdominal cavity, causing a swollen abdomen) and certain types of kidney disease. Spironolactone is used to remove excess fluid associated with these conditions and thus relieve the related symptoms.
Most other diuretics cause the amount of potassium in the blood to drop. Spironolactone doesn't have this effect, and so is called a 'potassium-sparing' diuretic. It is usually used in combination with other diuretics to increase the removal of fluid from the body, while preventing potassium levels from falling too low.
Spironolactone is also used in the treatment of a condition called Conn's syndrome, in which there is excess production of aldosterone by the adrenal glands. By opposing the action of aldosterone, spironolactone relieves the symptoms of this syndrome, which include fluid retention, high blood pressure and low levels of potassium in the blood.
What is it used for?
Congestive heart failure.
Liver cirrhosis where there is associated fluid retention (oedema) and collection of fluid in the abdominal cavity (ascites).
Progressively worsening fluid accumulation in the abdominal cavity (malignant ascites).
A kidney disorder called nephrotic syndrome, in which there is inflammation in the kidneys that results in too much fluid in the body, causing swelling, weight gain and high blood pressure.
Syndrome in which there is excess production of aldosterone by the adrenal glands (primary hyperaldosteronism or Conn's syndrome).
As diuretics cause your kidneys to produce more urine, you may prefer to take this medicine in the morning rather than before going to bed, as this will reduce the likelihood of you needing to get up in the night to visit the toilet. Seek further advice from your doctor or pharmacist.
This medicine may make some people feel sleepy or dizzy. You should take care when driving or operating machinary until you know how this medicine affects you and you are sure you can perform such activities safely.
It is recommended that people taking this medicine have their fluid and salt (electrolyte) balance monitored regularly.
If you experience any of the following symptoms while taking this medicine you should inform your doctor promptly, so that the amount of fluids and salts in your body can be checked: thirst, lethargy, confusion, weakness, drowsiness, muscle cramps, scanty production of urine, abnormal heart rhythm, seizures, nausea or vomiting.
Use with caution in
Decreased kidney function.
Decreased liver function.
Hereditary blood disorders called porphyrias.
Not to be used in
Severely decreased or rapidly worsening kidney function.
Sudden decrease in kidney function (acute renal insufficiency).
Failure of the kidneys to produce urine (anuria).
People with high levels of potassium in their blood (hyperkalaemia).
People with inadequate production of natural steroid hormones by the adrenal glands (Addison's disease).
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
This medicine should be used with caution during pregnancy, and only if the expected benefit to the mother is greater than any possible risk to the foetus. Seek medical advice from your doctor.
This medicine passes into breast milk in small amounts. The manufacturer recommends that mothers who need treatment with this medicine should not breastfeed, and bottlefeed their infants instead. Seek further medical advice from your doctor.
Take this medication with or after food.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain.
Abnormal enlargement of breasts in men (gynaecomastia).
Irregular menstrual cycle
Increased level of potassium in the blood (hyperkalaemia).
Decreased level of sodium in the blood (hyponatraemia).
Changes in sex drive.
Hair loss (alopecia).
Excessive hair growth.
Abnormal liver function.
Decreased numbers of white blood cells in the blood.
The side effects listed above may not include all of the side effects reported by the drug's manufacturer.