Under federal law, people addicted to a controlled substance are prohibited from buying a gun, said Joshua Horwitz, executive director of the Coalition to Stop Gun Violence.

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There is no reasonable therapeutic alternative to the use of the otherwise prohibited substance.

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Should a prohibited substance be found then the lab will ensure that the testing process has been done properly and that no mistakes could have happened along the way.

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The FAW, like most governing bodies in sport, has a strict anti-doping code that holds a player liable for failing a test, even though he may not have deliberately taken a prohibited substance.

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"She had listed the product believing in good faith it was something permitted and there was no way she could be aware it contained a prohibited substance, " said Denis Oswald, president of the International Rowing Federation and an IOC executive board member.

BBC: Rower fails drugs test

Stilnox, used to treat insomnia, is not considered a performance enhancer and is not a banned substance, but the Australian Olympic Committee (AOC) put it on the prohibited list ahead of the Games.

BBC: Australian Olympic swimmers admit using sedative