Amiloride

Amiloride HCl is indicated as adjunctive treatment with thiazide diuretics or other kaliuretic-diuretic agents in congestive heart failure or hypertension to: a. help restore normal serum potassium levels in patients who develop hypokalemia on the kaliuretic diuretic b. prevent development of hypokalemia in patients who would be exposed to particular risk if hypokalemia were to develop, e.g., digitalized patients or patients with significant cardiac arrhythmias. The use of potassium-conserving agents is often unnecessary in patients receiving diuretics for uncomplicated essential hypertension when such patients have a normal diet. …

• Amiloride HCl should be administered with food
• Amiloride HCl, one 5 mg tablet daily, should be added to the usual antihypertensive or diuretic dosage of a kaliuretic diuretic
• The dosage may be increased to 10 mg per day, if necessary
• More than two 5 mg tablets of amiloride HCl daily usually are not needed, and there is little controlled experience with such doses
• If persistent hypokalemia is documented with 10 mg, the dose can be increased to 15 mg, then 20 mg, with careful monitoring of electrolytes
• In treating patients with congestive heart failure after an initial diuresis has been achieved, potassium loss may also decrease and the need for amiloride HCl should be re-evaluated
• Dosage adjustment may be necessary
• Maintenance therapy may be on an intermittent basis
• If it is necessary to use amiloride HCl alone (See INDICATIONS ), the starting dosage should be one 5 mg tablet daily
• This dosage may be increased to 10 mg per day, if necessary
• More than two 5 mg tablets usually are not needed, and there is little controlled experience with such doses
• If persistent hypokalemia is documented with 10 mg, the dose can be increased to 15 mg, then 20 mg, with careful monitoring of electrolytes

• Safety and effectiveness
• In pediatric patients have not been established

Clinical studies of amiloride HCl did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. …

• Hyperkalemia Amiloride HCl should not be used in the presence of elevated serum potassium levels (greater than 5.5 mEq per liter)
• Antikaliuretic Therapy or Potassium Supplementation Amiloride HCl should not be given to patients receiving other potassium-conserving agents, such as spironolactone or triamterene. …

When amiloride HCl is administered concomitantly with an angiotensin-converting enzyme inhibitor, an angiotensin II receptor antagonist, cyclosporine or tacrolimus, the risk of hyperkalemia may be increased. Therefore, if concomitant use of these agents is indicated because of demonstrated hypokalemia, they should be used with caution and with frequent monitoring of serum potassium. (See WARNINGS .) Lithium generally should not be given with diuretics because they reduce its renal clearance and add a high risk of lithium toxicity. Read circulars for lithium preparations before use of such concomitant therapy. …

Hyperkalemia Like other potassium-conserving agents, amiloride may cause hyperkalemia (serum potassium levels greater than 5.5 mEq per liter) which, if uncorrected, is potentially fatal. Hyperkalemia occurs commonly (about 10%) when amiloride is used without a kaliuretic diuretic. This incidence is greater in patients with renal impairment, diabetes mellitus (with or without recognized renal insufficiency), and in the elderly. When amiloride HCl is used concomitantly with a thiazide diuretic in patients without these complications, the risk of hyperkalemia is reduced to about 1-2 percent. …

Amiloride HCl is usually well tolerated and, except for hyperkalemia (serum potassium levels greater than 5.5 mEq per liter — see WARNINGS ), significant adverse effects have been reported infrequently. Minor adverse reactions were reported relatively frequently (about 20%) but the relationship of many of the reports to amiloride HCl is uncertain and the overall frequency was similar in hydrochlorothiazide treated groups. Nausea/anorexia, abdominal pain, flatulence, and mild skin rash have been reported and probably are related to amiloride. …

Pregnancy Teratogenicity studies with amiloride HCl in rabbits and mice given 20 and 25 times the maximum human dose, respectively, revealed no evidence of harm to the fetus, although studies showed that the drug crossed the placenta in modest amounts. Reproduction studies in rats at 20 times the expected maximum daily dose for humans showed no evidence of impaired fertility. …

No data are available in regard to overdosage in humans. The oral LD 50 of amiloride hydrochloride (calculated as the base) is 56 mg/kg in mice and 36 to 85 mg/kg in rats, depending on the strain. It is not known whether the drug is dialyzable. The most likely signs and symptoms to be expected with overdosage are dehydration and electrolyte imbalance. These can be treated by established procedures. Therapy with amiloride HCl should be discontinued and the patient observed closely. There is no specific antidote. Emesis should be induced or gastric lavage performed. …

STORAGE Protect from moisture, freezing and excessive heat. Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature].

Take it when you remember, unless it is nearly time for the next dose. Then skip the missed one. Never take two doses at once to make up for it. Check your leaflet, as some medicines are different.