Description
Indications and Dosage
Oral Adult: Initially, 100-200 mg daily, may be gradually increased up to 400 mg daily for severe cases. Maintenance dose must be adjusted according to individual response. Oral Adult: Initially, 100 mg daily, may be adjusted up to 400 mg daily according to response. Oral Adult: For the management of oedema: Initially, 100 mg daily or 25-200 mg daily as a single dose or in divided doses. Maintenance dose must be adjusted according to individual response. Oral Adult: If glucocorticoids are insufficiently effective: Usual dose: 100-200 mg daily. Oral Adult: Long test: 400 mg daily for 3-4 weeks. Short test: 400 mg daily for 4 days. Oral Adult: Adjunct in patients who are not adequately controlled on other agents: As tab: Initially, 25-100 mg daily as a single dose or in divided doses. As susp: Initially, 20-75 mg daily a single dose or in divided doses. Dosage may be titrated at 2-week intervals, if needed, according to response and tolerability. Oral Adult: 100-400 mg daily. As long-term maintenance therapy in patients who are considered unsuitable for surgery: Use the lowest effective dose. Oral Adult: Initiate treatment in the hospital and slowly titrate the dose. If urinary Na/K ratio is >1: Initially, 100 mg daily. If urinary Na/K ratio is <1: Initially, 200-400 mg daily. Maintenance dose must be adjusted according to individual response. Oral Adult: In conjunction with standard therapy for the treatment of New York Heart Association (NYHA) Class III-IV cases: Patients with serum K ≤5 mEq/L and eGFR >50 mL/min/1.73 m2: As tab: Initially, 25 mg once daily, if tolerated, may be increased to 50 mg once daily as clinically indicated. As susp: Initially, 20 mg once daily, if tolerated, may be increased to 37.5 mg once daily as clinically indicated. Patients who develop hyperkalaemia on initial dose: As tab: May reduce dose to 25 mg every other day. As susp: May reduce dose to 20 mg every other day. |
Renal Impairment
Heart failure: |
Administration
Should be taken with food. |
Contraindications
Hyperkalaemia, Addison’s disease, anuria, acute renal insufficiency, diabetic nephropathy. Severe renal impairment. Children with moderate to severe renal impairment. Lactation. Concomitant use with eplerenone or other K-sparing diuretics, and K supplements (except in cases of initial K depletion). |
Special Precautions
Patient with diabetes mellitus, porphyria, menstrual abnormalities or breast enlargement; cirrhosis, predisposition to respiratory or metabolic acidosis, salt-depletion. Patient with heart failure: eGFR must be >30 mL/min/1.73 m2 or creatinine must be ≤2.5 mg/dL (men) or ≤2 mg/dL (women) with no recent worsening, and K <5 mEq/L with no history of severe hyperkalaemia. Discontinue use prior to adrenal vein catheterisation. Susp is not therapeutically equivalent to tab; patient requiring >100 mg/dose should use tab. Avoid unnecessary use. Renal and hepatic impairment. Children and elderly. Pregnancy. |
Adverse Reactions
Significant: Fluid-electrolyte imbalance (e.g. hypomagnesaemia, hyponatraemia, hypocalcaemia, hyperglycaemia), hyperchloraemic metabolic acidosis (reversible), asymptomatic hyperuricaemia, gout, gynaecomastia (reversible), symptomatic dehydration, hypotension, and worsened renal function; increased BUN (reversible). |
Patient Counseling Information
This drug may cause dizziness, drowsiness or somnolence, if affected, do not drive or operate machinery. Do not switch between dosage forms unless instructed by your doctor. |
MonitoringParameters
Monitor blood pressure, uric acid, blood glucose, renal function, volume status, and BUN periodically; serum electrolytes, including K (within 1 week of treatment initiation or dose titration, and regularly thereafter) and Na. Closely monitor serum K and renal function 3 days after initiating therapy, at 1 week after initiation, at least monthly for the 1st 3 months of treatment, and every 3 months thereafter for patient with heart failure. |
Overdosage
Symptoms: Drowsiness, dizziness, mental confusion, nausea, vomiting, diarrhoea, maculopapular or erythematous rash. Rarely, hyponatraemia, hyperkalaemia manifested as paraesthesia, flaccid paralysis, muscle weakness or spasm; hepatic coma. Management: Supportive treatment. Perform gastric lavage or induce vomiting. Maintain hydration, electrolyte balance and vital functions. For hyperkalaemia, may decrease K intake, administer K-excreting diuretics, IV glucose with regular insulin or oral ion-exchange resins. |
Drug Interactions
Reduced renal clearance of lithium thereby increased risk of lithium toxicity. Diuretic, natriuretic, and antihypertensive effects may be reduced by NSAIDs (e.g. aspirin, indometacin, mefenamic acid). May increase the serum levels of digoxin. May cause hyperkalaemic metabolic acidosis with colestyramine. May potentiate the hypotensive effects of antihypertensives. Effectiveness may be decreased by carbenoxolone. May reduce the vascular response to norepinephrine. May increase the risk of hyponatraemia with chlorpropamide. |
Food Interaction
Increased bioavailability with food. Orthostatic hypotension may be potentiated by alcohol. |
Lab Interference
May interfere with the radioimmunoassay of digoxin; may result to false negative aldosterone/renin ratio (ARR). May interfere with the estimation of compounds with similar fluorescence characteristics in fluorimetric assays. May enhance the metabolism of antipyrine used in LFTs. |
Action
Description: Spironolactone is a steroid with a structure that resembles aldosterone. It competitively inhibits aldosterone receptors in the distal convoluted renal tubules, thereby increasing the excretion of NaCl and water while conserving K and hydrogen ions. |
Chemical Structure
Spironolactone Source: National Center for Biotechnology Information. PubChem Database. Spironolactone, CID=5833, https://pubchem.ncbi.nlm.nih.gov/compound/Spironolactone (accessed on Jan. 23, 2020) |
Storage
Tab/susp: Store between 20-25°C. Protect from light and moisture. |
MIMS Class |
ATC Classification
C03DA01 – spironolactone ; Belongs to the class of aldosterone antagonists. Used as potassium-sparing diuretics. |