MOSCOW (AP) Maria Sharapova's ban for taking the banned substance meldonium has been reduced from two years to 15 months.
Although the drug led to a spate of positive tests from dozens of athletes, mostly in Eastern Europe, when it was banned for 2016, Sharapova is the only athlete serving a ban.
Here are some of the key issues surrounding meldonium:
Q: What is meldonium?
A: A Latvian-made drug available over the counter in Russia and other Eastern European and ex-Soviet countries, often without a prescription. The drug's manufacturer, Grindeks, says it is mostly aimed at people with heart conditions, though it can also be used for ''physical and psycho-emotional overload'' in otherwise healthy people. Meldonium's inventor, chemist Ivars Kalvins, has said it was given to Soviet soldiers fighting in Afghanistan to boost their stamina. However, Grindeks and Kalvins argue it shouldn't be banned in sports, with the manufacturer saying that it ''cannot improve athletic performance, but it can stop tissue damage'' during intense exercise. Sharapova said she took meldonium for a decade for reasons including a magnesium deficiency, family history of diabetes and dizziness. Meldonium is usually known by the brand name mildronate, though other names have been used.
Q: How was it banned?
A: The World Anti-Doping Agency said in September 2015 that meldonium would be banned as of Jan. 1, 2016, and published information on its website. A study conducted at the European Games in June 2015 and later published by the British Journal of Sports Medicine found 66 of 762 athletes taking meldonium, which the authors called ''excessive and inappropriate use ... in a generally heathy athlete population.'' After WADA's announcement, the International Tennis Federation notified players of changes to the list of banned substances by e-mail and using a ''wallet card'' distributed at tournaments, though CAS ruled Tuesday that this was inadequate. Sharapova tested positive at the Australian Open in January and said she was not aware meldonium had been banned.
Q: Who else tested positive?
A: After meldonium was banned, there were more than 170 failed tests by athletes, almost all from Eastern European countries, including Olympic medalists in sports ranging from figure skating to wrestling. Heavyweight boxer Alexander Povetkin of Russia saw his world title challenge called off after a failed test for meldonium.
Q: What happened to athletes who tested positive?
A: Almost all of the cases were dropped when athletes insisted they had stopped taking meldonium in 2015, before it was banned. The usually low concentrations of the drug in their samples backed up that argument, and WADA accepted findings of ''no fault or negligence'' in those cases. WADA also admitted it hadn't known enough about how long it took meldonium to leave an athlete's system. Sharapova's case was not dropped because she had continued taking meldonium after it was banned and the concentration in her sample was comparatively high.
Q: What next?
A: WADA confirmed last week that meldonium remains on the banned list for 2017. WADA's grace period for athletes who tested positive for low doses expired Friday, so any amount of the drug now triggers a positive test.