Other side effects include:

• Hallucinations
• Convulsions
• Brain hemorrhage
• Heart attack and other circulatory problems
• Heart palpitations
• Heart rhythm abnormalities
• Weight loss
• Mild hypertension

Diuretics

Diuretics are drugs that function to change your body's natural balance of fluids and salts (electrolytes) and can cause dehydration. This loss of water may allow an athlete to compete in a lighter weight class, which many athletes prefer. Diuretics also help athletes pass drug tests by diluting their urine.

Diuretics are commonly used to treat high blood pressure and conditions that cause fluid retention (edema), such as congestive heart failure. When taken in small amounts, they have relatively few side effects, although electrolyte disturbances can occur.

When taken at the higher doses preferred by some athletes, however, the adverse effects may be significant.

Using diuretics to achieve weight loss may cause:

• Potassium deficiency
• Heart arrhythmias
• Muscle cramps
• Exhaustion
• Decreased ability to regulate body temperature

Some of the most common diuretics include benzthiazide (Marazide, Aquastat),acetazolamide (Diamox, Storzolamide), spironolactone (Aldactone), dichlorphenamide (Daranide) and furosemide (Lasix, Fumide).

Gaining the competitive edge

Athletic performance has more to do with skill and hard work than taking a pill or downing a super-drink, according to Dr. Laskowski. Concern is growing that young athletes will copy sports figures who use substances of questionable value in a bid to gain a competitive edge.

"There's a danger that kids or young adults will think: 'If I want to be like that, I'll need to take something,'" says Dr. Laskowski. "There's a tendency to look for an external agent as a magic bullet, a magic pill that's going to help us perform. The truth is there isn't any."