Diuretics are drugs that cause urination by slowing down the reabsorption of water and sodium, or salt, in the kidneys. There are different categories of diuretics and each of these act on different sections of the kidneys where reabsorption takes place. Loop diuretics act on the ascending loop of Henle, thus they are called loop diuretics. They generally inhibit the reabsorption of salt and water in these sections of the kidney, in order to limit the amount of salt and fluid circulating in the body. These substances are instead passed out of the body with urination.
These diuretics are usually used for two main purposes. One is to reduce hypertension, or high blood pressure, and the other is to decrease fluid accumulation associated with liver, kidney, and heart diseases. These drugs are more potent than thiazide diuretics, another type of diuretics, as they inhibit reabsorption of salt more effectively.
Kidney, liver, and heart disorders are conditions that can cause edema or fluid accumulation and swelling in various parts of the body. Edema is commonly seen in the hands and feet. When it affects the lungs, breathlessness often occurs. These conditions can all benefit from the use of loop diuretics.
The most common side effects of diuretics of this type are fluid and electrolyte imbalances, such as decreased levels of magnesium, potassium, and sodium in the body. Calcium levels are also often elevated. These electrolytes are substances that are often needed by cells to function properly. Patients with these imbalances usually present with confusion, irregular heart beats, and weakness. Other side effects include rashes, muscles cramps, and nausea.
During treatment, patients are advised to avoid sudden movements such as sitting or standing up from a lying position. This frequently results in an orthostatic hypotension, which is the sudden decrease of blood pressure due to the swift change in position. Patients with diabetes and gout should also inform their physicians about these problems as the use of these kinds of diuretics can aggravate their symptoms.
Nephrologists, doctors who specialize in the treatment of kidney diseases, and cardiologists, doctors who manage patients with congestive heart failure, are usually the ones prescribing diuretics for their patients. They usually instruct patients to take this medicine in the morning and not in the evening. This practice is mainly to prevent frequent trips to the bathroom to urinate during the night, which can disturb sleep. Some kinds of loop diuretics are also best taken with meals in order to prevent stomach upset.