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How Diuretics Work

Diuretics cause your body to produce more urine. Urine flushes excess water and sodium out of your body. This lowers blood pressure because the more you urinate, the lower the volume of fluid in your bloodstream. Less fluid in your bloodstream means there is also lower pressure on your artery walls. In addition, the loss of excess sodium causes your blood vessels to open wider. This causes further lowering of your blood pressure. There are several different types of diuretics. They all work the same way by helping the kidneys to get rid of more sodium, potassium, and urine. Some diuretics also help your kidneys prevent minerals, such as potassium, from being excreted. One type of this medicine is called a potassium-sparing diuretic.

Precautions and Possible Side Effects

Precautions to take when you are on diuretics:

  • Be patient. When you begin taking this medicine, you may notice that you have to urinate more frequently than usual. Within a few weeks, as your body adjusts, you'll return to your normal patterns.
  • Ask your doctor if you need a supplement. Some diuretics can wash out key minerals along with the water and sodium that you want to get rid of. Potassium is one of the minerals that can be washed out. To counteract this, your doctor may want you to take a mineral supplement. Talk with your doctor about whether this applies to you. Never take supplements without your doctor's advice.
  • Protect your skin from the sun. Don't stay in the sun while you're on diuretics. They can make you more sensitive to the sun's effects. When outside, wear sunscreen and protective clothing.
  • Don't drink alcohol. You should not drink alcohol while taking this medicine. Doing so can cause problems.
  • Limit the amount of sodium in your diet to no more than 1 1/4 teaspoons each day. If you eat less salt, you may not need as much of your medicine to reduce your blood pressure. But you should never adjust the dose of your medicine yourself. Always talk with your doctor before making any changes.
Possible side effects of diuretics that you may notice:
  • headache
  • leg cramps
  • stomach upset
  • tiredness
  • excessive urination

Not everyone who takes diuretics will have these side effects. You should not be afraid to take your medicine because of the side effects listed. They are listed so that you can watch out for them and tell your doctor if you experience any of them.

Possible side effects of diuretics that you may not notice:

  • increased blood glucose levels
  • increased calcium
  • increased cholesterol
  • potassium loss
  • increased uric acid, which might trigger a gout attack in certain people

Although you may not be aware that your body is experiencing any of the above changes, your doctor will be able to test for these side effects during an office visit. Be sure to keep all follow-up appointments with your doctor.

Possible Drug Interactions with Diuretics

Before you take a diuretic, tell all of your doctors and your pharmacist about all the medicines you take. Include medicines you take for your blood pressure as well as for any other problem. Tell them about everything you take and how much you take each day, including all of the following:

  • prescription medicines
  • over-the-counter medicines
  • herbs
  • vitamin and mineral supplements

It's best to keep an updated list of these and bring a copy to give to your doctor. That way you can add to it whenever you take something new or delete the types you no longer take. Make a copy for each of your doctors so that they can keep it in your file. This complete list helps your doctor be better prepared to prescribe a diuretic that is the least likely to interact with your other treatments.