Aldosterone antagonists, also known as mineralocorticoid receptor antagonists (MRAs), block the effects of aldosterone to promote sodium excretion and potassium retention—commonly used to treat heart failure, hypertension, and conditions like hyperaldosteronism.
Name of the Aldosterone Antagonists drugs
- Spironolactone
- Eplerenone
Mechanism of Action:
Interferes with sodium reabsorption by competitively inhibiting action of aldosterone in distal tubule, promoting sodium and water excretion, increasing potassium retention. May decrease effect of aldosterone on arteriolar smooth muscle Aldosterone receptor antagonists have been shown to reduce heart failure-related hospitalizations, prolong life, and improve exercise tolerance and quality of life
Aldosterone antagonists are diuretics or “water pills.” They may also be called aldosterone receptor blockers.
| Spironolactone |
| Dosage Forms & Strengths: Adults: Tablet: 25mg, 50mg, 100mg Oral suspension (CaroSpir): 5mg/mL |
| Administration& handling: PO • Take with food to reduce GI irritation and increase absorption. Suspension: • Shake well. • May give with or without food (give consistently with respect to food). |
| Edema (For Cirrhosis) PO: ADULTS, ELDERLY: (Tablet): Initially, 100 mg/day as single dose. May titrate q3–5 days based on response and tolerability. Maximum dose: 400 mg once daily |
| Hypertension PO: ADULTS, ELDERLY: (Tablet): Initially, 12.5–25 mg once daily. May titrate q2wks as needed. Maximum: 100 mg. (Suspension): 20–100 mg daily in 1 or 2 divided doses. May titrate q2wks. |
| Primary Aldosteronism PO: ADULTS, ELDERLY: Initially, 12.5–25 mg once daily. Gradually titrate to the lowest effective dose. Maximum dose: 400 mg/day |
| HF PO: ADULTS, ELDERLY: (Tablet): Initially, 12.5–25 mg/day. May double the dose q4wks if serum potassium remains less than 5 mEq/L and renal function remains stable. Maximum: 50 mg/day. in 1 or 2 divided doses. (Suspension): Initially, 10–20 mg once daily. May titrate to 37.5 mg once daily if serum potassium remains less than 5 mEq/L and renal function remains stable. |
| Eplerenone |
| Availability: Tablets: 25 mg, 50 mg. |
| Administration/handling • Do not break, crush, dissolve, or divide film-coated tablets. • May give without regard to food. |
| Hypertension PO: ADULTS, ELDERLY: Initially, 50 mg once daily. If 50 mg once daily produces an inadequate B/P response, may increase dosage to 50 mg twice daily. If pt is concurrently receiving CYP3A4 inhibitors (e.g., erythromycin, verapamil, or fluconazole), reduce initial dose to 25 mg once daily. Maximum: 50 mg/day. |
| HF Following MI PO: ADULTS, ELDERLY: Initially, 25 mg once daily. If tolerated, titrate up to 50 mg once daily within 4 wks. |
Indication of Spironolactone:
- Congestive Cardiac Failure
- Oedema and ascites in cirrhotic patients
- Nephrotic Syndrome
- Primary Hyperaldosteronism (including Conn’s syndrome)
Indication of Eplerenone:
- Post –MI heart failure
Metabolism and Half- life
Metabolized to active metabolites. T ½ of drug is 60-90 min but t ½ of active metabolites is longer (up to 11 h)
Drug Interactions:
- Enhanced Hypotensive effect with other antihypertensives
- Increased risk of hyperkalemia with ACEIs/ARBs and amiloride.
- Increased risk of nephrotoxicity with NSAIDs
Cautions & Contraindications:
1.Electrolyte disturbances (including hyperkalemia and hyponatremia)
2.Caution in renal impairment
3.Alcohol can add to your medication’s drowsy effect.
4.Hypersensitivity Pregnancy & Lactation
Side – Effects:
- Hyperkalemia (K+ sparing effect)
- GI Disturbances
- Anti-androgenic effects (spironolactone – menstrual irregularities in females, gynecomastia and hypogonadism in males)
- Dizziness
- Dry Mouth
- Dehydration
- Hyponatremia
- Lethargy
NURSING CONSIDERATIONS
BASELINE ASSESSMENT
1.Weigh pt; initiate strict I&O.
2.Evaluate hydration status by assessing mucous membranes, skin turgor.
3.Obtain baseline serum electrolytes, renal/hepatic function, urinalysis.
4.Assess for edema; note location, extent.
5.Check baseline vital signs, note pulse rate/regularity.
INTERVENTION/EVALUATION
1.Monitor serum electrolyte values, esp. for increased potassium, BUN, creatinine. Monitor B/P.
2.Monitor for hyponatremia: mental confusion, thirst, cold/clammy skin, drowsiness, dry mouth.
3.Monitor for hyperkalemia: colic, diarrhea, muscle twitching followed by weakness/paralysis, arrhythmias.
4.Obtain daily weight. Note changes in edema, skin turgor.
5.Assist with ambulation if dizziness occurs.
PATIENT/FAMILY TEACHING
1.Expect increase in volume, frequency of urination.
2.Therapeutic effect takes several days to begin and can last for several days when drug is discontinued. This may not apply if pt is on a potassium-losing drug concomitantly (diet, use of supplements should be established by physician).
3.Report irregular or slow pulse, symptoms of electrolyte imbalance.
4.Avoid foods high in potassium, such as whole grains (cereals), legumes, meat, bananas, apricots, orange juice, potatoes (white, sweet), raisins.
5.Avoid alcohol.
6.Avoid tasks that require alertness, motor skills until response to drug is established (may cause drowsiness).
7.Avoid exercising during hot weather (risk of dehydration, hypotension).
Important Points:
1.Eplerenone is more selective than spironolactone and therefore causes fewer sex hormone related adverse effects.
2.Spironolactone may also be used in hypertension (Unlicensed indication)
3.Coadministration of spironolactone with potassium supplementation, salt substitutes containing potassium, a diet rich in potassium, or drugs that can increase potassium (e.g., ACE inhibitors, ARBs, NSAIDs, heparin and low molecular weight heparin) may lead to severe hyperkalemia
REFERENCES
- Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
- McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
- April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
- Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
- Nursebro.com, Search – Nursebro
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