spironolactone

spironolactone /spir·o·no·lac·tone/ (spi?rah-no-lak´ton) one of the spirolactones, an aldosterone inhibitor that blocks the aldosterone-dependent exchange of sodium and potassium in the distal tubule, thus increasing excretion of sodium and water and decreasing excretion of potassium; used in the treatment of edema, hypokalemia, primary aldosteronism, and hypertension.

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spi·ro·no·lac·tone (spr-n-lktn, sp-r-)

n.

An aldosterone antagonist and antiandrogen that promotes diuresis and is used to treat conditions characterized by hypertension and fluid retention as well as androgenic syndromes in women.

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spironolactone (spī´rnōlak´tōn),

n brand names: Aldactone, Spirozide;
drug class: potassium-sparing diuretic;
action: competes with aldosterone at receptor sites in distal tubule, resulting in excretion of sodium chloride and water and retention of potassium and phosphate;
uses: treatment for edema, hypertension, diuretic-induced hypokalemia, and cirrhosis of the liver with ascites.

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spironolactone

a competitive antagonist of aldosterone, used as a diuretic. It increases resorption of sodium in the distal renal tubules.

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spironolactone

Aldactone, Novo-spiroton (CA)

Pharmacologic class: Aldosterone inhibitor

Therapeutic class: Potassium-sparing diuretic

Pregnancy risk category D

FDA Boxed Warning

• Drug induced tumors in chronic toxicity studies in rats. Use only in conditions listed under "Indications and dosages." Avoid unnecessary use.

Action

Inhibits aldosterone effects in distal renal tubule, promoting sodium and water excretion and potassium retention

Availability

Tablets: 25 mg, 50 mg, 100 mg

⊘Indications and dosages

➣ Edema caused by heart failure, hepatic cirrhosis, or nephrotic syndrome

Adults: As sole diuretic, initially 100 mg/day P.O. (range of 25 to 200 mg) in single or divided doses, continued for 5 or more days and then adjusted to optimal therapeutic level

Children: 1 to 3 mg/kg/day P.O. as a single dose or in divided doses

➣ Essential hypertension

Adults: Initially, 50 to 100 mg/day P.O. as a single dose or in divided doses, continued for at least 2 weeks

Children: 1 to 2 mg/kg P.O. b.i.d.

➣ Hypokalemia

Adults: 25 to 100 mg/day P.O.

➣ Diagnosis and treatment of primary hyperaldosteronism

Adults: For diagnosis, 400 mg/day P.O. for 4 days in short test or for 3 to 4 weeks in long test. Resolution of hypokalemia and hypertension confirm diagnosis of primary hyperaldosteronism. Dosages of 100 to 400 mg/day P.O. may be used as a bridge to surgical therapy; in patients unsuitable for this therapy, lowest effective dosage may be used for long-term maintenance.

Off-label uses

• Acne vulgaris
• Familial male precocious puberty (given with other drugs)
• Premenstrual syndrome

Contraindications

• Hypersensitivity to drug
• Anuria
• Acute or chronic renal insufficiency
• Hyperkalemia
• Concurrent use of other potassium-sparing diuretics (such as amiloride, triamterene) or potassium supplements

Precautions

Use cautiously in:
• hepatic dysfunction, diabetes mellitus, fluid and electrolyte imbalances
• elderly or debilitated patients
• pregnant or breastfeeding patients
• children (safety not established).

Administration

• Give single daily dose with breakfast. If two daily doses are prescribed, give second dose with food in mid-afternoon.

Route	Onset	Peak	Duration
P.O.	Unknown	1-2 hr	2-3 days

Adverse reactions

CNS: headache, drowsiness, lethargy, ataxia, confusion

GI: vomiting, diarrhea, cramping, gastritis, GI ulcers, GI bleeding

GU: gynecomastia, irregular menses or amenorrhea, postmenopausal bleeding, erectile dysfunction, breast cancer

Hematologic: agranulocytosis

Metabolic: hyponatremia, hyperchloremic metabolic acidosis , hyperkalemia

Skin: rash, pruritus, hirsutism

Other: deepening of voice, drug fever

Interactions

Drug-drug. Angiotensin-converting enzyme inhibitors, potassium-sparing diuretics, potassium supplements, other potassium-containing drugs: increased risk of hyperkalemia

Anticoagulants, heparin: reduced hypoprothrombinemic effects of these drugs

Digoxin: increased digoxin blood level

Salicylates: decreased diuretic effect

Drug-diagnostic tests. Blood urea nitrogen, potassium: increased levels

Digoxin assays: false digoxin elevation

Granulocytes: decreased count

Drug-food. Potassium-containing salt substitutes: increased risk of hyperkalemia

Drug-herbs. Licorice: potassium loss

Patient monitoring

☞ Monitor electrolyte levels (especially potassium). Watch for signs and symptoms of imbalances and metabolic acidosis.
• Monitor weight and fluid intake and output. Stay alert for indications of fluid imbalance.
• Monitor CBC with white cell differential.

Patient teaching

• Tell patient to take daily dose with breakfast. If two daily doses are prescribed, advise him to take second dose with food in mid-afternoon.
• Advise patient to restrict intake of high-potassium foods and to avoid licorice and salt substitutes containing potassium.
• Tell male patient drug may cause breast enlargement.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.