Class: Potassium Sparing/Thiazide Diuretic Combination
Dosage Forms. Capsule: (Triamterene/Hydrochlorothiazide) 37.5 mg/25 mg, 50 mg/25 mg; Tablet: (Triamterene/Hydrochlorothiazide) 37.5 mg/25 mg, 50 mg/25 mg, 75 mg/50 mg
Common FDA Label Indication, Dosing, and Titration.
1. Edema: 37.5 mg/25 mg, 1-2 tablets or capsules po daily
2. Hypertension: 37.5 mg/25 mg, 1 tablet or capsule po daily, may titrate to 75 mg/50 mg po daily
Off-Label Uses. None
MOA. Triamterene acts directly from the distal tubular lumen on active sodium exchange for potassium and hydrogen, producing a mild diuresis that is independent of aldosterone concentration. Antihypertensive activity is inconsistent and less pronounced than with thiazides or spironolactone. Hydrochlorothiazide is a thiazide diuretic that increases sodium and chloride excretion by interfering with their reabsorption in the cortical diluting segment of the nephron; a mild diuresis of slightly concentrated urine results.
Drug Characteristics: Triamterene/Hydrochlorothiazide
Medication Safety Issues: Triamterene/Hydrochlorothiazide
Drug Interactions: Triamterene/Hydrochlorothiazide
Adverse Reactions: Triamterene/Hydrochlorothiazide
Efficacy Monitoring Parameters. Decreased blood pressure, reductions in edema.
Toxicity Monitoring Parameters. Altered serum and urine electrolytes (calcium, magnesium, potassium, sodium), decreased renal function (increased SCr or decreased urine output), increased serum uric acid or blood glucose. Seek medical attention if skin rash, yellowing of eyes or skin, or decreased urine output occurs or symptoms of gout occur.
Key Patient Counseling Points. May cause dizziness. Avoid driving, using machinery, or doing anything else that could be dangerous if not alert. Avoid alcohol and NSAIDs. May cause photosensitivity; use sunscreen. Use with caution in patients with sulfonamide allergy.
Clinical Pearls. Safety and effectiveness not established in children.