Interacting drugs - summary

 Amiloride +

Digoxin

in six healthy subjects, amiloride increased the renal clearance and decreased the nonrenal clearance of digoxin. It also apperared to decrease the inotropic effect of digoxin.

Potassium prepn 

concurrent administration may result in severe hyperkalemia, possibly with cardiac arrhythmias or cardiac arrest. Avoid concomitant use.

 ACE inhibitors

 use of ACE inhibitors may result in elevated serum potassium concentration. Concurrent use with amiloride may lead to significant hyperkalemia.

 NSAIDs

 NSAIDs may reduce the therapeutic effect of amiloride. Also, since indomethicin may be associated with increased potassium levels , consider this effect when amiloride is used concurrently.

Adjunctive treatment with thiazide or loop diuretics in congestive heart failure CHF or hypertion

CNS-

Headache, dizziness, encephalopathy, paresthesia, tremors, vertigo, nervousness, mental confusion, insomina,decreeased libido, depressin, somnolence.

GI-

Nausea, anorexia, diarrhea, vomiting, abdominal pain, gas pain, appetite changes, constipation, jaundice, GI bleeding, GI disturbances, abdominal fullness, thirst, dry mouth, heartburn, flatluence, dyspepsia, activation of probable preexisting peptic ulcer, abnormal liver function.

Metabolic-

Elevated serum potassium levels Musculoskeletal- weakness, fatigue, muscle cramps, joint/back/cjest pain, neck or shoulder ache, pain if the extremities.

Respiratory-

Cough, dyspnea, shortness of breath GU-impotence, polyuria, dysuria, urinary frequency, bladder spasms.

Cardiovascular-

Angina pectoris, orthostatic hypotension, arrhyhthmia, palpiations.

Dermatologic-

Skin rash, itching, pruritus, alopecia Special senses- visual disturbances, nasal congestion, tinitus, increased intraocular pressure. Hematologic- aplastic anemia, neutropenia.

Hypersensitivity to amilorideserum potassium, renal function impairment.

Special precautions

Electrolyte imbalance and BUn increases- hyponatremia and hypochloremia may occur when amiloride is used with other diuretics.. Increases in BUN levels usually accompnay vigorous fluyid elimination , especially when diuretic therapy is used in seriously ill patients, such as those who have hepatic cirrhosis with ascites and metabolic alkalosis or those with resistent edema.

Warnings:

Hyperkalemia- Amiloride may cause hyperkalemia (serum potassium . 5.5mEq/L) which if uncorreected is potentially fatal. Hyperkalemia occurs commonly (about 10% ) when amiloride is used alone.

Treatment- Discontinue the drug immediately. Monitor ECG and serum potassium levels. If seerum potassium levels exceeds 6.5mEq/L take active measures to reduce it including IV sodium bicarbonate solution or oral or parentral glucose with rapid acting insulin.

Diabetes mellitus- hyperkalemia has occured with the use of amiloride even in patients without evidence of diabetic nephropathy. If possible avoid use of amiloride in diabetic patients. If it is used monitor serum electrolytes and renal function frequently.

Metabolic or respiratory acidosis- cautiously institute amiloride in severely ill patients in whom respiratory or metabolic acidosis may occur, such as patients with cardiopulmonary disease or poorly controlled diabetes.

Renal function impairment- anuria acute or chronic renal insufficiency and evidence of diabetic nephropathy are contraindications because potassium retention is accentuated and may result in rapid development of hyperkalemia.

Do not give to patients with evidence of renal impairment (BUN > 30mg/dl or serum creatinine 1.5mg/dl ) or diabetes mellitus without continous monitoring of serum electrolytes, creatinine and BUN levels.

Hepatic function impairment- in patients with preexisting severe liver disease hepatic encephalopathy. manifested by tremors, cinfusion, and coma, and increased jaundice may occur in association with amiloride.

Because amiloride is not metabolised by the liver drug accumulation is not anticipated in patients with hepatic dysfunction, but accumulation may occur if hepatorenal syndrome develops.

Pregnancy- safety for use during pregnancy has not been established. Use only when clearly needed.

Lactation- because of the potential for serious adverse reactions in nursing infants, decide whether to discontinue nursing or discontinue the drug taking into account the importance of the drug to the mother.

Children- safety and efficacy for use in children has not been established.

Indications-

Adjunctive treatment with thiazide or loop diuretics in congestive heart failure CHF or hypertension.

Dosage-

Administer with food

Single dose therapy- Starting dose is 5mg/day . Increase it to 10mg/day if necessary. Doses more than 10mg are usualy not needed.

Overdosage- Symptoms Most likely signs are dehydration and electrolyte imbalance

Treatment

1. Discontinue therapy and observe patient closely.

2. Induce emesis or perform gastric lavage.

3. Treatment is symptomatic and supportive

Missed dose

1. If you miss a dose of this medicine, take it as soon as possible.

2. However, if it is time for your next dose, skip the missed dose and go back to your regular dosing schedule.

3. Do not double doses.

1.May cause GI upset , take with food.

2. Notify physician if any of the following occurs- muscular weakness, fatigue, muscle cramps.

3. May cause dizziness, headache, or visual disturbances, observe caution while driving or performing tasks requiring alertness, coordination or physical dexterity

4. Avoid large quantities of potassium rich food.

Pharmacology

Amiloride and triamterene not only inhibit reabsorption induced by aldosterone but they also inhibit basal sodium reabsorption. They are not aldersterone antagonists but act directly on renal distal tubule , cortical collecting tubule and electric -potential difference and inhibit transport of sodium and potassium.

Pregnancy:

Safety for use during pregnancy has not been established. Use only when clearly needed.

Lactation-

Because of the potential for serious adverse reactions in nursing infants, decide whether to discontinue nursing or discontinue the drug taking into account the importance of the drug to the mother.

Children-

Safety and efficacy for use in children has not been established.