Dyazide
Meaning of Dyazide: A two-in-one water pill, pairing a diuretic that wastes potassium with one that conserves it.
Definition of Dyazide
Dyazide is a brand name for a fixed combination of two diuretics, triamterene and hydrochlorothiazide, taken by mouth for raised blood pressure and for fluid retention. Hydrochlorothiazide prompts the kidneys to pass more salt and water, and potassium is lost with it. Triamterene acts further along the kidney tubule and holds potassium back, offsetting that loss.
What does each ingredient do?
The two drugs act at different points in the kidney, which is the reason for pairing them.
| Ingredient | Class | Effect on potassium |
|---|---|---|
| Hydrochlorothiazide | Thiazide diuretic | Increases loss |
| Triamterene | Potassium-sparing diuretic | Reduces loss |
Hydrochlorothiazide provides most of the effect on blood pressure. Triamterene contributes relatively little to that on its own and is present mainly to protect potassium levels.
Why combine two diuretics?
Low potassium is the most familiar drawback of thiazide treatment, and it can disturb heart rhythm. Combining the thiazide with a potassium-sparing agent keeps the salt and water loss while blunting the potassium loss, in one tablet. The pairing is not free of risk in the opposite direction: potassium can rise too high instead, particularly when kidney function is reduced or when other medicines that raise potassium are taken alongside it.
What is it used for?
The two established uses are high blood pressure and edema, the swelling that follows fluid building up in tissue, whether from heart failure, liver disease or kidney disease. The same triamterene and hydrochlorothiazide combination is sold under other brand names and as a generic, in more than one strength.
What does a diuretic actually do?
The kidney filters a large volume of fluid and then reclaims most of the salt and water back into the bloodstream. A diuretic blocks part of that reclaiming, so more salt leaves in the urine and water follows it. Two things result. The volume of fluid in the circulation falls, which relieves swelling, and the walls of the arteries relax over subsequent weeks, which is where much of the lasting reduction in pressure comes from. This is why the effect on swelling appears within hours while the effect on pressure builds gradually.
Also known as
Used in a sentence
The chart listed dyazide among the regular medications taken for hypertension.
Good to know
The combination pairs a potassium-wasting thiazide with a potassium-sparing agent, so potassium can move in either direction and is monitored rather than assumed to stay level.