What are the indications and usage of Triamterene?

Triamterene: Indications and Usage

Triamterene is indicated for treating edema associated with congestive heart failure, cirrhosis, nephrotic syndrome, steroid-induced edema, idiopathic edema, and secondary hyperaldosteronism, either alone or combined with other diuretics for its potassium-sparing properties. 1

Primary Indications

Edematous Conditions

• Congestive heart failure with fluid retention is a primary indication, where triamterene may be used alone or combined with thiazide or loop diuretics 1
• Cirrhosis of the liver with associated edema 1
• Nephrotic syndrome 1
• Steroid-induced edema and idiopathic edema 1
• Secondary hyperaldosteronism, particularly when patients prove resistant or only partially responsive to thiazides or other diuretics 1

Hypertension Management

• Combination therapy with hydrochlorothiazide to prevent hypokalemia while maintaining antihypertensive efficacy 2
• Add-on therapy in patients receiving other antihypertensive drug classes, with usual maintenance dosing of 1-2 mg/kg/day up to 300 mg/day 2
• Triamterene enhances blood pressure lowering beyond its potassium-sparing effect, reducing systolic BP by 1-4 mmHg when added to hydrochlorothiazide 3

Dosing Guidelines

Adult Dosing

• Initial dose: 100-200 mg daily in divided doses, typically combined with 50 mg hydrochlorothiazide 4
• Maximum dose: 300 mg/day 2
• Once-daily dosing is effective with optimally bioavailable formulations 5

Pediatric Dosing

• Initial dose: 1-2 mg/kg/day 2
• Maximum dose: 3-4 mg/kg/day up to 300 mg/day 2

Critical Contraindications and Precautions

Absolute Contraindications

• Significant renal dysfunction (GFR <45 mL/min) due to hyperkalemia risk 2
• Concurrent use with other potassium-sparing diuretics (amiloride, spironolactone) increases hyperkalemia risk 6, 2

Drug Interactions Requiring Monitoring

• ACE inhibitors or ARBs: Significantly increased hyperkalemia risk; close potassium monitoring mandatory 6, 2
• NSAIDs: Risk of acute renal failure, particularly concerning with over-the-counter availability 6, 7
• Potassium supplements or high-potassium salt substitutes: Avoid concurrent use 6
• Trimethoprim/trimethoprim-sulfamethoxazole: Additive hyperkalemia risk 6

Monitoring Requirements

Initial Phase

• Check potassium, creatinine, and electrolytes 1-2 weeks after initiation 6
• Recheck 1-2 weeks after each dose adjustment 6

Maintenance Phase

• Monitor blood chemistry every 4 months during stable therapy 6
• Stop triamterene if potassium rises >5.5 mmol/L 6
• Reduce or stop if creatinine increases >50% above baseline or reaches 266 μmol/L (3 mg/dL) 6

Clinical Considerations

Combination Therapy Advantages

• Synergistic effect with hydrochlorothiazide: Potentiates diuresis while minimizing potassium loss 8, 4
• Particularly valuable in digitalized patients: Prevents hypokalemia-related arrhythmias and digitalis toxicity 8
• Long-term management of chronic edema: Especially useful in diuretic-resistant patients 8

Pregnancy Considerations

• Not recommended for routine use in healthy pregnant women 1
• May be appropriate for pathologic edema (not physiologic pregnancy edema) after careful risk-benefit assessment 1
• Short courses only if extreme discomfort from edema unrelieved by rest 1

Common Pitfalls to Avoid

• Do not use triamterene alone as first-line heart failure therapy; always combine with ACE inhibitors and beta-blockers 6
• Avoid in elderly patients with creatinine clearance <30 mL/min due to impaired tubular secretion and hyperkalemia risk 6
• Do not combine with multiple potassium-retaining agents without intensive monitoring 6
• Warn patients about over-the-counter NSAIDs and potassium-containing salt substitutes 6