By Marcello Cherchi, MD PhD
For patients
Triamterene and hydrochlorothiazide are diuretic medications (“water pills”) that are sometimes combined into a single drug (marketed in the United States as Dyazide® and Maxzide®). They are used to help patients with some types of high blood pressure and swelling. They are sometimes also used to treat Ménière’s disease.
For clinicians
Practical summary
Triamterene (a potassium sparing diuretic) and hydrochlorothiazide (a potassium wasting diuretic) are sometimes combined to achieve a potassium neutral effect. These diuretics were originally used in the treatment of hypertension and edema. In otoneurology they are sometimes used for the prophylactic management of Ménière’s disease, though the evidence for their efficacy is mixed.
Introduction
Triamterene and hydrochlorothiazide are diuretics of different classes (Kehrenberg and Bachmann 2022) that were originally designed for the treatment of hypertension and edema. Triamterene is a potassium sparing diuretic, whereas hydrochlorothiazide is a potassium wasting diuretic, so they are sometimes combined with the intention of achieving a “potassium neutral” effect. In the United States the combination of triamterene and hydrochlorothiazide has been marketed under the brand names of Dyazide® and Maxzide®.
Triamterene: mechanism of action, adverse effects
Triamterene was originally used in the treatment of hypertension, edema and certain forms of cardiac failure.
Triamterene acts in the nephron at the late distal convoluted tubule and collecting duct by blocking epithelial sodium channels, thereby inhibiting sodium reabsorption from the lumen. This reduces intracellular sodium, decreasing the function of sodium-potassium-ATPase, resulting in retention of potassium (hence the “potassium sparing” property), and reduces the excretion of calcium, magnesium and hydrogen.
Aside from the intended diuretic effect, triamterene’s potential adverse effects include electrolyte imbalances (disorders of potassium), elevated liver enzymes, and the formation of kidney stones.
Hydrochlorothiazide: mechanism of action, adverse effects
Hydrochlorothiazide (HCTZ) is a thiazide diuretic that inhibits sodium reabsorption in the distal convoluted tubule, resulting in increased excretion of potassium (hence the “potassium wasting” property), sodium, water and hydrogen.
Hydrochlorothiazide was originally used in the treatment of hypertension and edema.
Aside from the intended diuretic effect, hydrochlorothiazide’s potential adverse effects include electrolyte imbalances (hypokalemia, hypomagnesemia, hypercalcemia, hyponatremia), hyperuricemia (which may precipitate gout), visual disturbances (transient myopia, acute angle closure glaucoma).
Hydrochlorothiazide crosses the placenta and has been reported to cause fetal/neonatal jaundice and thrombocytopenia. Hydrochlorothiazide is present in breast milk. Hydrochlorothiazide should be used with caution in women who are pregnant, trying to become pregnant, or nursing.
Relevance in otoneurology
The main application of triamterene and hydrochlorothiazide in otoneurology is in the prophylactic management of Ménière’s disease, though the evidence in favor of its efficacy is mixed at best, with some studies supporting its use (van Deelen and Huizing 1986) and others not (Thirlwall and Kundu 2006).
References
Kehrenberg MCA, Bachmann HS (2022) Diuretics: a contemporary pharmacological classification? Naunyn Schmiedebergs Arch Pharmacol 395: 619-627. doi: 10.1007/s00210-022-02228-0
Thirlwall AS, Kundu S (2006) Diuretics for Meniere’s disease or syndrome. Cochrane Database Syst Rev: CD003599. doi: 10.1002/14651858.CD003599.pub2
van Deelen GW, Huizing EH (1986) Use of a diuretic (Dyazide) in the treatment of Meniere’s disease. A double-blind cross-over placebo-controlled study. ORL J Otorhinolaryngol Relat Spec 48: 287-92.
