SPIRACTIN Tablet Ref.[50295] Active ingredients: Spironolactone

Concomitant use of spironolactone with angiotensin converting enzyme (ACE) inhibitors, non-steroidal antiinflammatory drugs, angiotensin II antagonists, aldosterone blockers, heparin, low molecular weight heparin, other drugs or conditions known to cause hyperkalaemia or potassium supplements, a diet rich in potassium, including salt substitutes containing potassium, or other potassium sparing agents is not recommended as it may lead to severe hyperkalaemia.

Hyperkalaemia may be fatal in patients with severe heart failure (New York Heart Association [NYHA] Class III-IV). Potassium and creatinine levels should be closely monitored one week after initiation or monthly for the first 3 months, then quarterly for a year, and then every 6 months when increasing the dose of spironolactone. See Use in Renal Impairment.

Use in Hepatic Impairment

Reversible hyperchloraemic metabolic acidosis, usually in association with hyperkalaemia, has been reported to occur in some patients with decompensated hepatic cirrhosis, even in the presence of normal renal function.

Use in Renal Impairment

Concomitant use of spironolactone and other potassium-sparing diuretics in patients with severe heart failure should be avoided. If serum potassium >3.5 mEq/L, oral potassium supplements should be avoided. Treatment with spironolactone should be discontinued or interrupted in patients with serum potassium >5 mEq/L or with serum creatinine >4 mg/dL.

Use in the Elderly

Periodic estimation of serum electrolytes is desirable due to the possibility of hyperkalaemia, hyponatraemia and possible transient blood urea nitrogen (BUN) elevation, especially in the elderly and/or in patients with pre-existing impaired renal or hepatic function, in whom the risk/benefit ratio should always be weighed.

Paediatric Use

No data available.

Effects on Laboratory Tests

Spironolactone can interfere with assays for plasma digoxin concentrations.

Concomitant use of drugs known to cause hyperkalaemia with spironolactone may result in severe hyperkalaemia (see Section 4.4 SPECIAL WARNINGS AND PRECAUTIONS FOR USE).

Hyperkalaemia has been associated with the use of either indometacin or angiotensin converting enzyme (ACE) inhibitors in combination with potassium sparing diuretics.

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

Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, indometacin, and mefenamic acid may attenuate the natriuretic efficacy of diuretics due to inhibition of intrarenal synthesis of prostaglandins and have been shown to attenuate the diuretic effect of spironolactone.

As carbenoxolone may cause sodium retention and thus decrease the effectiveness of spironolactone, concurrent use of the two agents should be avoided.

Spironolactone 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 digoxin dose when spironolactone is administered, and the patient should be carefully monitored to avoid over- or under-digitalisation.

Spironolactone may have an additive effect when given concomitantly with other diuretics and antihypertensive agents. The dose of such drugs may need to be reduced when spironolactone is added to the treatment regimen.

Spironolactone enhances the metabolism of antipyrine.

Hyperkalaemic metabolic acidosis has been reported in patients given spironolactone concurrently with ammonium chloride or colestyramine.

Spironolactone binds to the androgen receptor and may increase prostate-specific antigen (PSA) levels in abiraterone-treated prostate cancer patients.

Effects on fertility

The safety of spironolactone for the treatment of hirsutism in women of childbearing age has not been established by specific long-term clinical trials. Epidemiological studies are also inadequate to establish the safety of long-term use in this population.

See Section 5.3 PRECLINICAL SAFETY DATA.

Use in pregnancy

Pregnancy Category B3.

Experimentally, passive transfer of potassium sparing diuretics across the human placenta has been demonstrated. Maternal treatment during pregnancy may result in electrolyte disturbances in the foetus.

Spironolactone should not be used in pregnancy (see Section 4.3 CONTRAINDICATIONS). Women of childbearing potential should employ adequate contraception (i.e. oral contraceptives or IUDs) during administration of spironolactone, and the drug should be stopped if pregnancy occurs or is suspected.

Use in lactation

Canrenone, an active metabolite of spironolactone, appears in breast milk. An alternative method of infant feeding should be instituted if the use of the drug is deemed essential.

Somnolence and dizziness have been reported to occur in some patients. Caution is advised when driving or operating machinery until the response to initial treatment has been determined.

Gynaecomastia may develop in association with the use of spironolactone, and physicians should be alert to its possible onset. The development of gynaecomastia appears to be related to both dosage level and duration of therapy and is normally reversible when spironolactone is discontinued. In rare instances, some breast enlargement may persist.

Other adverse reactions that have been reported in association with spironolactone are: gastrointestinal symptoms including cramping, diarrhoea, nausea, vomiting, gastric bleeding, ulceration and gastritis; drowsiness, lethargy, headache, maculopapular or erythematous cutaneous eruptions, urticaria; mental confusion, drug fever, ataxia, inability to achieve or maintain erection, irregular menses or amenorrhoea, postmenopausal bleeding, malaise, benign breast neoplasm, breast pain, leucopenia (including agranulocytosis), thrombocytopenia, abnormal hepatic function, electrolyte disturbances, hyperkalaemia, leg cramps, dizziness, changes in libido, Steven-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms (DRESS), alopecia, hypertrichosis, pruritus, rash and acute renal failure.

Carcinoma of the breast has been reported in patients taking spironolactone, but a cause and effect relationship has not been established.

Reporting Suspected Adverse Effects

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at www.tga.gov.au/reporting-problems.

See Section 4.5 INTERACTIONS WITH OTHER MEDICINES AND OTHER FORMS OF INTERACTIONS.

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.