Osmotic Diuretics
These are injectable drugs that act on the kidneys by essentially instructing the kidneys to release everything that comes in. Osmotic diuretics are non-discriminatory, meaning they remove any and all water that comes to the kidneys, regardless of proper electrolyte balance. These drugs override the function of the kidneys and can cause renal (kidney) failure. Osmotic diuretics are not overly common in bodybuilding.
Potassium-sparing Diuretics
These diuretics are milder, however create problems of their own. They reduce the re-absorption of sodium and water through the kidneys and flush them out of the body. They do, however discriminate by not flushing potassium(K) from the system. While these are slower acting and more tolerable, they can cause an excess of K in the body as they do not allow it to flush and keep the balance of electrolytes intact. This can cause, in extreme cases, cardiac dysrythmia (irregular heartbeats) and even sudden death in the most extreme cases.
Loop Diuretics
These are far and away the most commonly used diuretics in bodybuilding and the culprit in the vast majority of bodybuilding hospitalizations and deaths. Furosimide (brand name Lasix) is easily the most widely used loop diuretic and is cheap and readily available. Loop diuretics are used medicinally to treat high blood pressure and edema; and in cases of blood poisoning are used to flush the blood of toxins and foreign agents. Loop diuretics act directly on the kidneys and are another non-discriminatory diuretic in that they remove any and all fluids coming through the kidneys. They have a profound effect on the electrolyte balance as they literally flush potassium, sodium and calcium from the body with whatever fluid enters. Side effects include a drop in blood pressure, thickening of the blood (due to lack of fluids), fainting, renal failure, extreme cramping due to electrolyte imbalances, and death (due to muscular cramping of the heart). The drug is extremely powerful and, combined with other water reduction techniques employed by bodybuilders in contest preparation, it doesn’t take much Lasix to cause extremely detrimental health effects.
