The effects of diuretics, which are substances that increase the rate and volume of urine production by the kidneys, on the body are quite varied and definitely significant. There are many different kinds of diuretics, and the most commonly used classes are carbonic anhydrase inhibitors, loop diuretics, thiazide diuretics and potassium-sparing diuretics. While each class exerts its effect on a particular segment of the kidney through its own unique mechanism of action, all classes of diuretics ultimately cause increased excretion of various electrolytes, including sodium, potassium and calcium, in the urine.
A greater urinary loss of water subsequently accompanies the excretion of electrolytes (in particular, sodium), because sodium ions tend to pull water molecules together with them. Thus, more sodium and water lost in urine equals a larger volume of urine. Aside from the different classes of diuretics, some herbs are also commonly used in traditional medicine systems worldwide as safe and efficient diuretics. Examples of these herbs are dandelion, mint, nettle, parsley, saffron, sage, saw palmetto and St. John’s wort.
Diuretics and Body Water
Since diuretics promote the loss of water in urine, these substances are often used in conditions where there is an abnormal retention of fluid in the body. Typical uses of diuretics are for edematous states such as congestive heart failure, liver cirrhosis and nephrotic syndrome (the excessive loss of protein in urine). Diuretics are also a mainstay in the treatment of hypertension, because a reduction in blood volume is associated with significant drops in blood pressure.
If you have kidney stones or are prone to developing urinary tract infections, you can also benefit from diuretics. The increased volume and flow of urine keep urine dilute, thus discouraging the precipitation of stones and the overgrowth of bacteria.
Diuretics are also often used to reduce water weight. While diuretics can indeed reduce weight, overzealous use is not without danger to your health and life. Unregulated use of these otherwise useful medications can easily lead to dehydration, dangerous drops in blood pressure and abnormalities in electrolytes. It is, therefore, unwise to use diuretics without the supervision of your physician.
Diuretics and Electrolytes
Your body requires optimal levels of electrolytes, such as sodium and potassium, in order to function properly. Diuretics can easily disrupt the tight balance of these electrolytes by promoting and increasing their excretion in urine.
Chronic use of most diuretics causes depletion of the sodium and potassium contents of the body. The loop and thiazide diuretics, in particular, are notorious causes for dangerously low sodium concentrations in blood, a condition known as hyponatremia. Severe hyponatremia causes swelling of nerve cells and can lead to seizures, coma and even death.
Diuretics also derange normal potassium concentrations in blood. Maintaining normal concentrations of potassium is necessary in preserving the normal transmission of electrical signals in nerves, muscles and the heart. Abnormally high or low concentrations of potassium, which are conditions called hyperkalemia and hypokalemia, respectively, lead to muscle weakness and abnormal heart rhythms. In severe hyperkalemia or hypokalemia, the heart may stop beating altogether.