Concerns When Taking Diuretics for Hypertension

One of the most common types of blood pressure medications is known as a diuretic. These medicines lower your blood pressure by helping your body get rid of excess water and salt through your kidneys, allowing your heart to pump better.

Diuretics are commonly known as "water pills" and they treat several conditions, including hypertension (high blood pressure), heart failure, and kidney problems. For blood pressure, they may be used alone or added to another medication.

Classes of diuretics include:

  • Thiazide diuretics
  • Loop diuretics
  • Potassium-sparing diuretics
Nurse taking patient blood pressure in living room
John Fedele / Getty Images

Thiazide Diuretics

Thiazide diuretics are used to treat blood pressure and also to get rid of excess fluid, or edema, in patients with heart failure, liver disease, steroid use, and estrogen-replacement therapy.

Some common thiazide diuretics used to treat hypertension include:

  • Hydrochlorothiazide
  • Indapamide
  • Chlorothiazide
  • Metolazone
  • Chlorthalidone

Loop Diuretics

Loop diuretics are used to treat edema in congestive heart failure as well as kidney and liver disease. They work by blocking the reabsorption of fluid that passes through your kidneys, and then you pass that excess fluid as urine.

Other loop diuretics are:

  • Lasix (furosemide)
  • Bumex (bumetanide)
  • Demadex (torsemide)
  • Edecrin (ethacrynic acid)

Potassium-Sparing Diuretics

Potassium-sparing diuretics are often used at the same time as other diuretics to maintain the potassium balance in your body. They don't lower blood pressure significantly when used alone. Potassium-sparing diuretics include:

  • Aldactone
  • Spironolactone
  • Amiloride
  • Triamterene

Side Effects

Diuretics can cause numerous side effects, including some that may be dangerous. The specific side-effect profile is different for each drug, so you'll want to get familiar with the one(s) you're taking.

In general, some common side effects of diuretics include:

  • Frequent urination: You may need to urinate more often than usual after taking a diuretic. This symptom usually subsides after a few hours.
  • Electrolyte imbalance: You can lose electrolytes (including sodium and potassium, depending on the drug) in your urine when you are taking a diuretic, so your doctor may monitor your blood chemistry while you're taking these drugs.
  • Weakness and fatigue: These side effects usually resolve after a few weeks, as you get used to the drug.
  • Muscle cramps: This can occur when a diuretic leads to low potassium levels. In some cases, doctors recommend a daily potassium supplement for their patients on diuretics. Don't just assume you need one, though. This is a decision that's best made with your doctor.
  • Dizziness, blurred vision: These symptoms can result from dehydration. Watch for symptoms, which include decreased urine output, excessive thirst or mouth dryness, or dark-colored urine. Let your doctor know the drug could be dehydrating you.

Less common side effects are:

  • Increase in blood sugar levels in diabetics
  • Attacks of gout
  • Impotence in men (rarely)

As with any drug, diuretics sometimes cause dangerous side effects. Contact your doctor right away if you notice any of the following symptoms:

  • Fever
  • Sore throat and mouth ulcers
  • Unexplained bleeding or bruising
  • Ringing in your ears

Do you have an allergy to sulfa drugs? Many diuretic drugs contain sulfa, so tell your doctor if you have an allergy to sulfa (or any medication). Making sure this information is in your chart and on file with your pharmacy can help protect you from getting a drug that you shouldn't take.

Important Concerns

Dozens of different antihypertensive medications are on the market, and each one has its pros and cons. Your doctor can go over the risks and benefits with you. Your pharmacist is also a great resource for information about how medications may affect you.

To protect your health, you should be aware of several things about taking diuretics to control your hypertension.

  • When you doctor prescribes a diuretic (or any drug), make sure they're aware of any medications—prescription or over-the-counter—that you're taking. This includes nutritional supplements and herbal remedies, as well.
  • Consider taking your diuretic in the morning, so you won't be up at night going to the bathroom.
  • While you're on a diuretic, your doctor may want to monitor your blood pressure, electrolyte levels, and kidney function regularly, so be certain to keep all of your appointments as scheduled.
  • Remember that diuretics can cause abnormal levels of potassium or sodium. If you're taking a potassium-sparing diuretic, your doctor may tell you to avoid foods that are rich in potassium. These foods include some salt substitutes.
  • Women who are pregnant or breastfeeding shouldn't use diuretics.
  • Lifestyle factors, like smoking and salty foods, can keep your medicine from working effectively. Let your doctor know if you need help or guidance giving up cigarettes or making healthy changes to your diet.

Managing Your Blood Pressure

Keeping your blood pressure at a good level is important to your health, and prescription drugs are only part of the solution to hypertension. It can also help if you:

  • Take your medicines as prescribed
  • Check your blood pressure at the same time each day, if your doctor wants you to track it

Lifestyle changes may help you control your blood pressure with lower doses of medication, or they may allow you to go off of medication altogether. These include:

  • Eating a healthy diet
  • Maintaining a healthy weight
  • Exercising regularly
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Article Sources
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  1. Duarte JD, Cooper-DeHoff RM. Mechanisms for blood pressure lowering and metabolic effects of thiazide and thiazide-like diuretics. Expert Rev Cardiovasc Ther. 2010;8(6):793–802. doi:10.1586/erc.10.27

  2. U.S. National Library of Medicine, StatPearls. Thiazide Diuretics. Updated February 4, 2019.

  3. U.S. National Library of Medicine, StatPearls. Loop Diuretics. Updated October 15, 2019.

  4. Elsevier ScienceDirect. Hypokalemia: Adjuncts to Therapy. Published 2017.

  5. American Heart Association. Types of Blood Pressure Medications. Reviewed October 31, 2017.

  6. National Health Service, UK. Furosemide. Reviewed January 10, 2019.

  7. Johns Hopkins Lupus Center. Blood Pressure Medications (Anti-hypertensives).

  8. Leone A. Does Smoking Act as a Friend or Enemy of Blood Pressure? Let Release Pandora's Box. Cardiol Res Pract. 2011;2011:264894. Published 2011 Jan 19. doi:10.4061/2011/264894

  9. Harvard Health Publishing, Harvard Medical School. Tips for Taking Diuretic Medications. Updated September 25, 2019.

  10. American Heart Association. Changes You Can Make to Manage High Blood Pressure. Reviewed November 30, 2017.