What are diuretics and how do they lower your blood pressure?
By Martha Funnell, MS, RN, CDE
There are several kinds of medicines that help to lower blood pressure. One category of medicine that some people with diabetes take to lower blood pressure is called diuretics. These are commonly called “water pills” because they help the body eliminate extra salt and water through the urine.
If you take a diuretic, you may notice that you go to the bathroom more often. If so, try taking it in the morning so you do not have to get up so often at night. If you are getting up more often at night, be sure to stand up slowly and keep a nightlight on so you are less likely to fall or trip over something.
Another side effect that you may notice from diuretics is that your mouth may feel dry. Taking sips of water or sugar-free fluids, chewing sugarless gum or hard-candies or chewing ice chips may also be helpful.
As with most medicines, if your dose is too high, you could have more serious side effects. Your blood glucose may go up and men may have difficulty having an erection. Be sure to tell your health care provider if you notice either of these effects.
Another serious side effect of diuretics involves changes in your potassium level. Potassium is one of the chemicals in your blood known as electrolytes, and is important for normal heart and nervous system function. Other electrolytes that may also be affected include sodium, magnesium, calcium, phosphate and bicarbonate. Electrolytes help maintain the right amount of water in your body, and help your muscles and nerves work correctly. Your body keeps your electrolyte levels in a very tight range. When taking diuretics, electrolytes can be lost in the urine along with the salt and water.
Signs of an electrolyte imbalance include thirst, weakness, lethargy, drowsiness, restlessness, muscle pain and cramps, seizures, lack of urine production, much lower blood pressure and severe stomach upset. Most people do not need to take extra potassium when taking a diuretic, but check with your health care provider to see if you need to take potassium to keep your electrolytes in balance.
Reviewed by Robert Ehrman, MD