I think that as long as the drug itself isn't illegal in the country you are performing in, and it doesn't put your immediate health and safety or the immediate health and safety of those around you at risk, then it should be free game to use for a competition. In all sports.

The only real concern is not the 'purity of the game' but the long-term health risks of doing these drugs and how that may affect younger people who look up to athletes as heroes and want to be like them.