Information last reviewed: May 2026 — for educational purposes only.
What Is Triamterene?
Triamterene (brand name Dyrenium) is a potassium-sparing diuretic that works by blocking epithelial sodium channels (ENaC) in the cortical collecting duct of the kidney. Unlike thiazide and loop diuretics, triamterene promotes sodium excretion without increasing potassium loss, making it useful for preventing or correcting hypokalaemia (low potassium). Its diuretic effect is weaker than loop or thiazide agents when used alone; it is most frequently prescribed in combination with hydrochlorothiazide under the brand names Dyazide (37.5 mg/25 mg) or Maxzide (75 mg/50 mg).
Prescription (Rx) Status
Triamterene is prescription-only. It is not available over the counter. Monitoring of serum potassium and renal function is required during therapy, particularly in patients with kidney disease, diabetes, or those taking ACE inhibitors or ARBs, due to the risk of hyperkalaemia (high potassium).
Uses of Triamterene
Indications include: oedema associated with heart failure, hepatic cirrhosis, or nephrotic syndrome; hypertension (usually in combination with a thiazide); and prevention of diuretic-induced hypokalaemia. The combination pill Dyazide/Maxzide is among the most commonly prescribed antihypertensive diuretic combinations in the United States.
Capsule Strengths
Triamterene is available as capsules: 50 mg and 100 mg. When supplied as the combination Dyazide: Triamterene 37.5 mg / Hydrochlorothiazide 25 mg capsules. Typical dosing: 50–100 mg once or twice daily, or as directed by the prescriber.
Price
Generic triamterene capsules are modestly priced. The combination Dyazide/Maxzide generic is widely available for approximately $15–$30 for a 30-day supply depending on the pharmacy and insurance coverage.
Frequently Asked Questions
Q: Why is triamterene combined with HCTZ?
A: HCTZ lowers potassium; triamterene retains potassium. Together they counterbalance each other's electrolyte effects, providing effective diuresis with reduced hypokalaemia risk.
Q: Can triamterene cause high potassium?
A: Yes — hyperkalaemia is the main risk, especially in patients with kidney disease or those on potassium supplements or ACE inhibitors. Regular blood tests are recommended.
Q: Is Dyazide the same as Maxzide?
A: Both contain triamterene + HCTZ, but Maxzide is more bioavailable. Doses differ slightly; only your prescriber should switch you between them.
Disclaimer: This page is for informational purposes only and does not constitute medical advice. Triamterene requires a valid prescription. Always consult a qualified healthcare professional. See our full disclaimer.