Blood Pressure Medications: Diuretics ("Water Pills")

Diuretics increase the kidneys' excretion of salt (sodium) and water, decreasing the volume of fluid in the bloodstream and the pressure in the arteries. Diuretics are the oldest and most studied antihypertensive agents.

One of the most commonly used diuretic agents is hydrochlorothiazide (HydroDiuril, Microzide). Other diuretics used to treat hypertension include the following:

  • Acetazolamide (Diamox)
  • Furosemide (Lasix)
  • Indapamide (Lozol)
  • Metolazone (Zaroxolyn)
  • Spirnolactone (Aldactone)
  • Torsemide (Demadex)
  • Triamterene (Dyrenium)

Combination medications that contain both a diuretic and a different class of antihypertensive agent are being produced.

The main side effect of these agents is increased frequency of urination. Another side effect is increased urinary excretion of potassium. Because of this, doctors monitor blood potassium levels when initiating therapy and periodically thereafter. Patients who have low potassium levels are encouraged to eat foods rich in potassium, such as bananas, or may be prescribed a potassium supplement.

Aliskiren (Tekturna) is a medication that can be used alone or in combination with other antihypertensive agents to treat high blood pressure. It is often used with diuretics and an angiotensin-receptor blocker (ARB). This medication should not be used during pregnancy.

In April 2012, the makers of Valturna, a combination of aliskiren and valsartan approved in 2009, agreed to pull this drug from the U.S. market and the Food and Drug Administration (FDA) issued a warning against using medications containing aliskiren in patients with diabetes or kidney problems (renal impairment). This warning was issued in response to early clinical trial data indicating an increased risk for kidney damage, hypotension (very low blood pressure) and hyperkalemia (high potassium levels) in people with diabetes who take aliskiren combined with angiotensin converting enzyme inhibitors (ACE inhibitors) and angiotensin receptor blockers (ARBs) to treat high blood pressure. Talk to your doctor if you have been prescribed a blood pressure medication containing aliskiren.

Publication Review By: Jagdish Patel, M.D., F.A.C.C.

Published: 30 Jun 2000

Last Modified: 21 Jan 2015