Triamterene

FDA label

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Renal Contraindicated in anuria and in severe or progressive kidney disease or dysfunction (possible exception: nephrosis)

Hepatic Contraindicated in severe hepatic disease; observe cirrhotics for exacerbation of underlying liver disease

Instructions

• Take after meals to reduce stomach upset; if QD, prefer morning dosing
• Discontinue all potassium supplementation when adding to or switching from other diuretics
• When combined with another diuretic or antihypertensive, lower the initial daily dose of each agent, then adjust
• Monitor serum potassium frequently (especially renal impairment, diabetes, elderly, severely ill); periodic BUN, creatinine and blood counts

Contraindications

• Anuria
• Severe or progressive kidney disease or dysfunction (possible exception: nephrosis)
• Severe hepatic disease
• Pre-existing elevated serum potassium, or hyperkalemia developing on the drug
• Dietary potassium supplements, potassium salts, or potassium-containing salt substitutes
• Other potassium-sparing agents (spironolactone, amiloride, other triamterene-containing formulations) — deaths reported with concomitant spironolactone

Cautions

• Hyperkalemia (K+ >=5.5 mEq/L) can occur and may be fatal if uncorrected — monitor potassium frequently; obtain ECG if hyperkalemia suspected
• Highest hyperkalemia risk: renal impairment, diabetes (even without renal impairment), elderly, severely ill
• Idiosyncratic blood dyscrasias and liver damage — observe regularly
• Electrolyte imbalance in CHF, renal disease, cirrhosis; possible metabolic acidosis; mild reversible nitrogen retention
• Weak folic acid antagonist — megaloblastosis risk with depleted folate stores (e.g., cirrhotics); periodic blood studies
• Elevates uric acid (gout predisposition); caution with history of renal stones (triamterene found in stones)

Adverse reactions

• Hyperkalemia
• Hypokalemia
• Azotemia / elevated BUN and creatinine
• Renal stones
• Acute interstitial nephritis (rare)
• Acute renal failure (one irreversible case)
• Jaundice / liver enzyme abnormalities
• Nausea/vomiting
• Diarrhea
• Thrombocytopenia
• Megaloblastic anemia
• Weakness/fatigue
• Dizziness
• Headache
• Dry mouth
• Anaphylaxis
• Rash
• Photosensitivity

Pregnancy No fetal harm in rat studies up to 20x MRHD; crosses placenta into cord blood; use only if clearly needed — routine diuretic use in healthy pregnant women is inappropriate

Lactation Undefined