From Velo...
http://velonews.competitor.com/2012/...dium=whats-hot
[h=2]The Substance[/h] Xipamide is a prescription-only, orally administered diuretic drug. It is also knows as Diurexan, the brand name under which it may be found in a pharmacy. A doctor typically prescribes the drug, in tablet form, to a patient dealing with high blood pressure. In these cases, high blood pressure is caused not by arterial fat buildup, but by high sodium levels in the blood. Since water follows solutes (solid matter), high levels of sodium in the blood will cause increased water retention in the bloodstream as well, putting excess strain on the heart as it tries to move the extra fluid.
Diuretics are typically used in sport as masking agents. Although that term is a misnomer, as diuretics don’t actually mask anything, they conceal the presence of a drug by helping to flush it from the body through increased urination. Using this effect, an athlete could use Xipamide to help remove traces of banned substances prior to a doping control.