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Athletes competing at the Olympics in Rio have been taking a hard line against their peers who've been accused of doping. But competitors can actually still engage in a form of doping that is legal. NPR's Jon Hamilton reports on the practice of taking prescription drugs that may improve performance but haven't been banned yet.
JON HAMILTON, BYLINE: Most people had never heard of a drug called meldonium until tennis champion Maria Sharapova admitted using it in March. That admission is why she won't be competing in Rio. But endurance athletes knew about meldonium. And until the World Anti-Doping Agency banned the drug in January, lots of competitors were taking it.
RONALD EVANS: If it's not banned, athletes will use it.
HAMILTON: That's Ronald Evans of the Salk Institute in San Diego. He's an expert on drugs that affect metabolism. Evans says meldonium is just one of a group of prescription heart drugs that could help a runner or a swimmer last longer.
EVANS: Those are really thought to improve blood flow. You improve blood flow, you improve more oxygen getting to the muscles that you want. And therefore, it's good for performance.
HAMILTON: Meldonium was around for decades before it got banned. And since the ban, it's been found in samples from about 100 athletes. Meanwhile, competitors can still legally use another prescription heart drug called telmisartan. Evans says this drug also improves blood flow in a way that could give an athlete an advantage.
EVANS: It is not prohibited. And if it's not prohibited, that means you almost have to seriously consider it unless you are so much better than your competitors.
HAMILTON: The World Anti-Doping Agency has been monitoring telmisartan since 2015. But Evans says meldonium and telmisartan are just bit players in the doping world. It's not even clear how effective they are. What athletes really want, he says, is the kind of drug he's been working on for years.
EVANS: A drug that promotes the benefits of fitness without actually training.
HAMILTON: Evans isn't trying to help dopers. He's trying to save the lives of people with health problems like obesity and diabetes. But he knows that any prescription drug that comes from his work will find its way into competitive sports.
EVANS: I get emails from athletes, coaches, the horse racing industry (laughter).
HAMILTON: Doping authorities are also interested in new drugs that can alter metabolism. Olivier de Hon is the manager of scientific affairs for the Anti-Doping Authority in the Netherlands.
OLIVIER DE HON: It is true that over the last few years, yeah, there are more and more inventive medicines which might be performance-enhancing as well.
HAMILTON: De Hon says it can take years to assess a potential doping drug. One reason is that it's hard to find information on the performance-enhancing qualities of a substance. De Hon says this was particularly true of meldonium.
DE HON: Most of the scientific literature that's available about meldonium, it's in Russian. And I cannot read that. So I had some problems in making up my mind whether - what we should do with it.
HAMILTON: And de Hon says you are not going to keep athletes from doping simply by banning lots of drugs. It often comes down to the culture of a particular country or a particular sport. De Hon says, take cycling, for example, a sport where doping has been rampant.
DE HON: Within the world of cycling they realized at one point that this is not the sport anymore that they can sell to the public and can sell to the people who pay for them.
HAMILTON: De Hon says doping appears to be less common in cycling these days because the sport has changed, not because there's more testing. Jon Hamilton, NPR News.
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