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What Is Chlorothiazide?

Christina Whyte
Christina Whyte

Chlorothiazide is a diuretic tablet, or water pill, which is used to treat high blood pressure and various conditions that cause water retention, also known as edema. It works by increasing urine flow so that more water and salt are passed from the body. Chlorothiazide is generally a safe medication, but it does have some potential side effects and there are precautions that should be taken when it is prescribed.

Particularly when starting treatment, patients taking this medication will need to urinate more frequently. It should be taken regularly according to the directions given when prescribed, but this usually allows for taking it when it is not going to cause problems for the patient. For example, taking it before bed would result in the need to urinate frequently during the night. After taking chlorothiazide for a while, the frequency of urination should reduce.

A medical professional checks a man's blood pressure. Chlorothiazide can be used to treat high blood pressure.
A medical professional checks a man's blood pressure. Chlorothiazide can be used to treat high blood pressure.

There are a number of side effects that may be caused by taking chlorothiazide besides frequent urination. The most common are lightheadedness, dizziness, headache, and blurred vision. Some serious side effects can occur, such as allergic reaction, decrease in urine output, or red and peeling skin. Patients should seek medical attention for any severe or concerning symptoms and ask a doctor about side effects to watch for.

Other drugs may interact negatively with chlorothiazide, some quite severely. It is important to tell the prescribing doctor about all other medications a patient is taking, including vitamins and herbs. The doctor also needs to know about any pre-existing health conditions, particularly liver, kidney, immune system disorders, and diabetes. This medication is not recommended while pregnant or breastfeeding, and a patient who becomes pregnant while taking it should contact her physician.

Even if the patient's high blood pressure reduces and the patient feels normal, he or she should not discontinue this medication. Keeping regular doctor appointments to check blood pressure is also very important even if the patient feels well. Chlorothiazide works by controlling high blood pressure and water retention, not by curing it.

Patients who are taking chlorothiazide may need to make lifestyle changes to supplement drug treatment. This may include regular exercise and a special diet, often a low sodium diet including potassium rich foods, such as bananas. If a patient experiences vomiting or diarrhea for any reason, such as the flu, he or she should contact a doctor. Losing a lot of bodily fluids combined with the effects of the medication can be dangerous.

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    • A medical professional checks a man's blood pressure. Chlorothiazide can be used to treat high blood pressure.
      By: Rob
      A medical professional checks a man's blood pressure. Chlorothiazide can be used to treat high blood pressure.