Product Information
Registration Status: ActiveSIN02222P
ALDACTONE TABLET 25mg is approved to be sold in Singapore with effective from 1988-06-29. It is marketed by PFIZER PTE LTD, with the registration number of SIN02222P.
This product contains Spironolactone 25mg in the form of TABLET. It is approved for ORAL use.
This product is manufactured by Piramal Healthcare UK LTD in UNITED KINGDOM.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Product Reference
Important Note: For generic product, the SPC/PIL provided may not be brand specific.
{{/items}} {{^items}}Description
A potassium sparing diuretic that acts by antagonism of aldosterone in the distal renal tubules. It is used mainly in the treatment of refractory edema in patients with congestive heart failure, nephrotic syndrome, or hepatic cirrhosis. Its effects on the endocrine system are utilized in the treatments of hirsutism and acne but they can lead to adverse effects. (From Martindale, The Extra Pharmacopoeia, 30th ed, p827)
Indication
Used primarily to treat low-renin hypertension, hypokalemia, and Conn's syndrome.
Mechanism of Action
Spironolactone is a specific pharmacologic antagonist of aldosterone, acting primarily through competitive binding of receptors at the aldosterone-dependent sodium-potassium exchange site in the distal convoluted renal tubule. Spironolactone causes increased amounts of sodium and water to be excreted, while potassium is retained. Spironolactone acts both as a diuretic and as an antihypertensive drug by this mechanism. It may be given alone or with other diuretic agents which act more proximally in the renal tubule. Aldosterone interacts with a cytoplasmic mineralocorticoid receptor to enhance the expression of the Na+, K+-ATPase and the Na+ channel involved in a Na+ K+ transport in the distal tubule . Spironolactone bind to this mineralcorticoid receptor, blocking the actions of aldosterone on gene expression. Aldosterone is a hormone; its primary function is to retain sodium and excrete potassium in the kidneys.
Pharmacokinetics
- Absorption
- Fairly rapidly absorbed from the gastrointestinal tract. Food increases the bioavailability of unmetabolized spironolactone by almost 100%.
- Distribution
- Metabolism
- Rapidly and extensively metabolized. The metabolic pathway of spironolactone is complex and can be divided into two main routes: those in which the sulfur moiety is retained and those in which the sulfur moiety is removed by dethioacetylation. Spironolactone is transformed to a reactive metabolite that can inactivate adrenal and testicular cytochrome P450 enzymes. It also has anti-androgenic activity.
- Elimination
Toxicity
The oral LD50 of spironolactone is greater than 1,000 mg/kg in mice, rats, and rabbits. Acute overdosage of spironolactone may be manifested by drowsiness, mental confusion, maculopapular or erythematous rash, nausea, vomiting, dizziness, or diarrhea. Spironolactone has been shown to be a tumorigen in chronic toxicity studies in rats.
Active Ingredient/Synonyms
Espironolactona | Spironolactone | Spironolactonum | Spironolattone | Spironolactone |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.