Articles Diuretics

How do Diuretics Work?

Diuretic pills and capsules

To function well the body needs to maintain a healthy balance of sodium and chloride (regular table salt). If this balance is upset complications may arise. Too much can result in oedema or high blood pressure. Too little can lead to muscle cramps, nausea, vomiting, seizures or even comas and death.

Certain medications, known as Diuretics, increase the volume of urine we pass. They mostly work by removing sodium and chloride from the body. Diuretics work by preventing the kidney from reabsorbing salt and water from the urine.

As sodium leaves your body, so too does the water it has absorbed. This increase in urine can be very helpful in lowering high blood pressure, and decreasing swelling in different parts of the body.

To address fluid retention, your doctor may ask you to consider taking additional minerals like zinc, potassium, and magnesium and may monitor your electrolyte (minerals) levels.


People may experience excess water retention for a variety of reasons. Sometimes this is a mild, temporary situation that is resolved through diet and exercise, rest and self-care. At other times, it can be far more serious.

  • People diagnosed with congestive heart failure may need to address excess water in the body because it can put additional strain on the heart.
  • Liver and kidney infection are other serious conditions where fluid retention becomes an issue. High blood pressure is also affected by higher fluid levels in the blood.
  • High blood pressure can be reduced when fluid volume in the blood vessels is reduced.


Because diuretics can interact with, and potentially increase the effects of other medications, there is always the risk that dangerous electrolyte abnormalities may occur (such as reduced levels of potassium). Medications designed to reduce fluid must be used with extreme caution and preferably under medical supervision. The kidneys are a finely tuned filtering and monitoring organ where the required amount of sodium and potassium is returned to the blood stream so that equilibrium is maintained while waste and excess water filters into the bladder as urine.

When we alter the body's electrolyte balance, levels of important minerals such as magnesium can be lowered and an imbalance of electrolytes may put us at higher risk for heart failure. That is why it is important to monitor sodium, potassium, and magnesium levels and the doctor is likely to also monitor kidney function and blood pressure.

Other drug interactions include: cyclosporine, antidepressants, lithium and digoxin.


  • Loss of potassium. Low blood levels of potassium may result in fatigue, mood swings, sleepiness, arrythmia and even heart failure.
  • Uric acid in the blood may increase. Uric acid is a waste product of metabolising proteins and is associated with gout.
  • Higher cholesterol. Carbohydrate metabolism is affected and can result in diabetes mellitus, especially in elderly patients, along with pancreatitis gallbladder problems, deafness and bladder weakness.
  • Lower Magnesium levels. Optimum magnesium levels are associated with fewer heart attacks, less arrhythmia and are thought to positively affect the symptoms associated with mitral valve prolapse.
  • Eating Disorders. Diuretics and drugs like laxatives are often used to control weight. Since they only decrease water, and not fat, in the body, this can result in dehydration,electrolyte imbalances and potassium deficiencies.
  • Side effects may include increased urination, muscle cramps, thirst, dry mouth, blood pressure changes, heart arrhythmia, tiredness, depression, anxiety, confusion, insomnia, nausea, vomiting, and constipation.

Are there Alternatives?

Exercise, weight loss, salt reduction, supplements and other techniques can help lower high blood pressure naturally. Fluid retention is often directly linked to weak adrenal glands. Your adrenal glands produce over 50 different hormones that regulate the sodium and potassium levels in your body. Natural Vitamin C (with bioflavonoids), Vitamin B6 (with magnesium) are also thought to help reduce water. Discuss alternatives with your doctor.