Taking a small dose of EPO does not carry the same health risks as taking anabolic steroids for example.
Steroids carry far more significant health risks than other performance enhancing drugs and should not be allowed under any circumstances. However, more mild drugs could be permitted in a controlled way without posing a serous threat to the athlete's health. If the drugs were permitted and heavily regulated, even the marginal health impacts could be radically minimized, allowing athlete's to take performance enhancing drugs safely.
It isn't just the health impacts that make doping unsuited to professional sport. Doping goes against the notion of equal competition, a core tenet of professional sport. Therefore, no doping should be permitted, even if it can be done with no risk to the athlete's health.
[P1] Some milder drugs can be taken safely without negative consequences on the athlete's health. [P2] These could be permitted in professional sports.
Rejecting the premises
[Rejecting P2] Doping, of any kind, runs counter to the spirit of professional sport.