Diuretics (Water Pills)
Commonly known as "water pills," these drugs help your kidneys get rid of extra water and salt from your body through your pee. Because you have less total fluid in your blood vessels, like a garden hose that's not turned on all the way, the pressure inside will be lower. This also makes it easier for your heart to pump.
They're usually the first type of medication that your doctor will try to control your blood pressure.
You'll often start with a thiazide diuretic:
- Chlorthalidone (Hygroton);
- Chlorothiazide (Diuril);
- Hydrochlorothiazide or HCTZ (Esidrix, Hydrodiuril, Microzide);
- Indapamide (Lozol);
- Metolazone (Mykrox, Zaroxolyn).
Take note of that word: prescribed. Water pills are meant to help reduce blood pressure, prevent fluid buildup, and reduce swelling respectively.
They're usually given to people with health issues like hypertension, heart failure, and idiopathic edema (unexplained swelling)—not people looking to cure mild bloating or lose weight. Most doctors recommend against using water pills for those purposes.
Side effects of diuretics
When taken as prescribed, diuretics are generally well tolerated. However, they can still cause some side effects.
More common side effects
The more common side effects of diuretics include:
- too little potassium in the blood
- too much potassium in the blood (for potassium-sparing diuretics only)
- low sodium levels
- increased blood sugar
- muscle cramps
- increased cholesterol
- skin rash
Serious side effects
In rare cases, diuretics may cause serious side effects. These can include:
- allergic reaction
- kidney failure
- irregular heartbeat
Warnings and Precautions
Don't take diuretics if you have trouble urinating, or if you're allergic to the active or inactive ingredients found in the medication.
How should I take my diuretic?
Always follow the instructions on the label. These medicines are usually taken in the morning. If you have been asked to take them twice a day take the second dose early in the afternoon. Avoid taking them at night otherwise you may have to wake up to go to the toilet. Don’t alter the amount of fluid that you normally drink while taking this medicine (a normal amount is approximately 2.5 to 3.5 pints of fluid per day, or 1.5 to 2 litres per day).
Can I take other medicines while taking diuretics?
Yes, but some other medicines may affect how diuretics work. It is important that you check with your doctor or pharmacist before taking any other medicines including ones that you buy over the counter. Avoid buying salt substitutes instead of ordinary table salt.
Tips for taking diuretics
- Because diuretics cause you to pass urine more often, it is best taken in the morning. Some people may need a second dose at lunchtime.
- Get to know how long it takes for your diuretic tablet to work after you have taken it, then you can plan your day around it. If you want to go out in the morning and don't want to have to find a toilet, you can delay taking your dose until lunchtime or early afternoon. Avoid taking your dose within 4 hours of your bedtime to prevent having to get up to urinate.
- If you are taking your diuretic for heart failure, the best way to know if it is working is to weigh yourself at the same time each day. Read more about medicines for heart failure.
- Limit or avoid drinking alcohol while you are taking your diuretic. Alcohol may increase your chances of getting side effects such as dizziness.
- Some people taking a diuretic may need to have regular blood and urine tests to check potassium and blood glucose levels. This is to make sure that all the chemicals in your blood stream are properly balanced.