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Diuretics are medicines used to increase the amount of water and salt excreted through urine. This drug is also commonly known as water pills. There are three common types of diuretics that can help treat high blood pressure and other conditions.

Types of Diuretics

There are three types of diuretic medicines: thiazide diuretics, loop diuretics, and potassium-sparing diuretics. All three of them help your body excrete more fluid through urine. 

Thiazide diuretics

Thiazides are the most commonly prescribed diuretics used to treat high blood pressure. These drugs not only reduce fluids, but also make blood vessels more relaxed. Thiazides are sometimes taken in conjunction with other medicines for treatment of lower blood pressure.

Loop Diuretics

This type of diuretics is often used to treat heart failure.

Potassium-Sparing Diuretics

This type of diuretics serves to reduce your body fluids without causing the loss of potassium as an essential nutrient to prevent arrhythmia problems. This medicine may be prescribed for people who are at risk for low potassium levels.

Potassium-sparing diuretics do not reduce blood pressure as effective as other types of diuretics. Therefore, your doctor may prescribe a potassium-sparing diuretics with other medications that can lower blood pressure.

Dosing Considerations for Diuretics

Take diuretics as exactly directed by your doctor.

Thiazide Diuretics

Condition: Hypertension

  • Dosage for adults: 500 to 1000 mg / day, maximum 2000 mg / day–can be administered in one or two separate doses.
  • Maintenance dosage for adults: 500 to 1500 mg / day.
  • Dosage for children aged < 2 years: 10-20 mg / kg / day, maximum 375 mg / day. It can be administered once a day or in two separate doses.
  • Dosage for children aged < 6 months: 30 mg / kg / day in two separate doses if necessary.
  • Dosage for children aged 2 to 12 years: 10-20 mg / kg / day (max 1000 mg / day. It can be administered once a day or in two separate doses.

Condition: Edema

  • Dosage for adults: 500 to 1000 mg as much as 1 to 2 times a day. Maximum 2000 mg / day.

Loop Diuretics

Condition: Hypertension

  • Initial dose for adults: 40 mg twice a day.
  • Maintenance dose for adults: titration according to the expected result. 

Condition: Edema

  • Initial dosage for adults: 20-80 mg, once a day.
  • Maintenance dose for adults: titration according to the expected result. Maximum 600 mg / day. Increase the dose with multiples of 20 to 40 mg / dose. The second dose can be administered 6 to 8 hours after the previous dose.
  • Initial dose for children: 2 mg / kg administered as a single dose.
  • Maintenance dose for children: titration according to the expected result. Maximum 6 mg / kg / dose. Increase the dose with multiples of 1 to 2 mg / kg / dose with an interval of 6 to 8 hours after the previous dose.

Indications for Diuretics

Diuretics can be used for treatment of:

  • Hypertension.
  • Osteoporosis.
  • Sequential nephron blockade.
  • Nephrogenic diabetes insipidus.
  • Prevention of kidney stones or calcium stones, idiopathic hypercalciuria.
  • Chronic edema secondary to congestive heart failure, cirrhosis (damage to the liver), and kidney disease.

Contraindications for Diuretics

Contraindications of diuretics may include:

  • Allergic reactions – for people with allergy to sulfa drugs. This is because some diuretics are sulfa drugs.
  • Older people tend to experience more side effects after using diuretics, such as fainting and dizziness due to dehydration. In this case, you must speak with a doctor.
  • Diuretics are not recommended for pregnant women, as it is unknown how the drug can affect unborn babies. 
  • It is also not recommended for nursing mothers – as many diuretics pass into breast milk, putting the baby at risk of dehydration.
  • Children are safe on diuretics, but they have to be given a smaller dose. The side effects are similar to those of adults. Potassium-sparing diuretics can cause low calcium levels, which can interfere with bone development.


Do not take diuretics if you have trouble urinating, allergies to active or inactive ingredients within the medicine. Ask your doctor if you should avoid or be careful when using diuretics if you: 

  • Have dehydration.
  • Suffer from gout.
  • Have irregular heartbeat.
  • Are 65 years old or older.
  • Are in the third trimester of pregnancy.
  • Have severe liver or kidney disease.
  • Experience high blood pressure during pregnancy.
  • Have allergy to sulfa drugs, such as Septra and Bactrim (sulfamethoxazole with trimethoprim).
  • Have taken drugs that can damage hearing, such as cancer drugs Platinol (cisplatin) and carboplatin.

Diuretics Drug Interactions

There are many medications that can interact with diuretics. Your doctor or pharmacist can make sure that you are not taking more than one diuretic at a time, unless the doctor tells you otherwise.

Do not use loop diuretics if you are using Tikosyn (dofetilide). Make sure your potassium is monitored closely if you use digoxin and diuretic loops or thiazide. Dosage of insulin and oral diabetes medications may need to be adjusted when using diuretics.

Ask your doctor about diuretics if you are using medications for mood swings such as Lithobids (lithium) or if you are taking medications that cause dehydration.

Some plants are considered natural diuretics, including shrubs, green tea, black tea, and parsley. This substance is not used as a substitute for diuretics. If you have questions about diuretics and other treatment options, it is best to talk to your doctor.

Side Effects of Diuretics

Diuretics are generally well tolerated when you take them as prescribed. However, such drugs are still at risk of causing some side effects such as:

  • Dehydration
  • Diarrhea.
  • Gout.
  • Muscle cramps.
  • Skin rash 
  • Low sodium levels.
  • Dizziness or headache.
  • Increased blood sugar and cholesterol.
  • Low level of potassium in the blood 
  • High level of potassium in the blood is too much (for potassium-sparing diuretics).

In rare cases, diuretics can cause more serious side effects including: 

  • Kidney failure.
  • Allergic reactions.
  • Irregular heartbeat.

If you have side effects when using diuretics, it is best to talk to your doctor. Your doctor may prescribe different medications or combinations of medications to help reduce your side effects.

Even if you experience or do not experience any side effects, do not stop taking diuretics without consulting a doctor first.

Risks of Diuretics

Diuretics are generally safe with some possible risks, particularly if you have other medical conditions or take certain medications. Before you are prescribed with diuretics, be sure to inform your doctor if you have any of the following conditions or problems:

  • Lupus.
  • Gout.
  • Diabetes.
  • Kidney problems.
  • Frequent dehydration
  • Acute pancreatitis.
  • Menstrual problems.

Consult your doctor or pharmacist through Smarter Health to find out the recommended dosage for diuretics. Smarter Health allows you access to healthcare services whenever you need them. 

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