Triamterene

A to Z Drug Facts

 Action Interferes with sodium reabsorption at distal renal tubule, resulting in increased excretion of sodium and water and decreased excretion of potassium.

 Indications Treatment of edema associated with CHF, hepatic cirrhosis and nephrotic syndrome; treatment of steroid-induced edema, idiopathic edema and edema caused by secondary hyperaldosteronism; management of hypertension in patient with diuretic-induced hypokalemia or at risk of hypokalemia.

 Contraindications Treatment with spironolactone or amiloride; anuria; severe hepatic disease; yperkalemia; severe or progressive kidney disease or dysfunction, with exception of nephrosis.

 Route/Dosage

ADULTS: PO 100 mg bid after meals (maximum 300 mg/day). CHILDREN: PO 2–4 mg/kg/day given in one dose or 2 divided doses (maximum 300 mg/day).

 Interactions

ACE inhibitors: May result in severely elevated serum potassium levels. Indomethacin: May cause rapid progression into acute renal failure. Potassium preparations and salt substitutes: May severely increase serum potassium levels, possibly resulting in cardiac arrhythmias or cardiac arrest. Do not take with potassium preparations.

 Lab Test Interferences May interfere with fluorometry such as quinidine serum levels and LDH determination.

 Adverse Reactions

CV: Hypotension. CNS: Weakness; fatigue; dizziness; headache. DERM: Photosensitivity; rash. GI: Diarrhea; nausea; vomiting; dry mouth. GU: Azotemia; elevated BUN and creatinine; renal stones; bluish discoloration to urine; interstitial nephritis. HEPA: Jaundice; liver enzyme abnormalities. HEMA: Thrombocytopenia; megaloblastic anemia. META: Hyponatremia; hyperchloremic metabolic acidosis; hyperkalemia. OTHER: Anaphylaxis; muscle cramps.

 Precautions

Pregnancy: Category B. Lactation: Undetermined. Adult-onset diabetes mellitus: Blood glucose levels may be increased; dosage adjustments of hypoglycemic agents may be needed. Concurrent diuretic therapy: Dosage reduction may be necessary. Electrolyte imbalances and BUN increase: Hyperkalemia (serum potassium > 5.5 mEq/l), hyponatremia, hyperchloremia and increases in BUN may occur. Monitor serum electrolytes and BUN levels. Hematologic effects: Triamterene is weak folic acid antagonist and may contribute to appearance of megaloblastosis. Metabolic acidosis: May decrease alkali reserve with possibility of metabolic acidosis. Renal impairment: Use drug with caution; monitor renal function. Renal stones: Triamterene has been found in renal stones. Use drug with caution in patients with history of stone formation.

 Administration/Storage

• Administer after meals.
• Administer once daily dose in morning to avoid disturbing sleep.
• Open capsules and mix with food or fluids if appropriate for patient needs.
• Store at room temperature in tight, light resistant container.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Assess renal status, BUN and creatinine levels and fluid and electrolyte status.
• Assess I&O, body weight and hydration status.
• Assess lung sounds and peripheral edema.
• Assess vital signs, especially BP.
• Institute safety precautions to prevent falls, particularly with initial doses.
• Monitor for signs and symptoms of hyperkalemia, especially with diabetic patients.
• Monitor for signs and symptoms of side effects, ie, hyperkalemia, GI disturbances, weakness, dizziness, unusual bleeding or bruising.
• Monitor patient for signs of metabolic acidosis; hyperventilation, drowsiness, restlessness.

 Patient/Family Education

• Tell patient to avoid salt substitute and limit potassium-rich foods.
• Inform patients taking antihypertensives that additive effects are possible; identify signs and symptoms of hypotension and precautions to be taken.
• Advise patient that medication may cause urine to become blue tinged.
• Explain potential GI side effects and to take medication after meals.
• Tell patient that drug may cause weakness, headache, nausea, vomiting or dry mouth and to notify physician if they become severe or persistent.
• Instruct patient to report these symptoms to physician: fever, sore throat, mouth sores or unusual bleeding or bruising.
• Caution patient to avoid intake of alcoholic beverages or other CNS depressants.
• Advise patient to use caution while driving or performing other tasks requiring mental alertness.
• Caution patient to avoid exposure to sunlight or ultraviolet light and to use sunscreen or wear protective clothing to prevent photosensitivity reaction.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts