Russian tennis player Maria Sharapova was warned at least five times in one month by tennis authorities that meldonium would be added to the list of banned substances, the Times newspaper reported Wednesday.
According to the Times, in December last year Sharapova received three letters from the International Tennis Federation and two letters from Women's Tennis Association, notifying her that meldonium would be added to the list of banned substances on Jan.1 2016, the RBC news website reported.
On Monday, Sharapova announced that she failed a drug test at the Australian Open in January. She had tested positive for meldonium, a drug Sharapova said she had been taking for ten years as a treatment for pre-diabetes. Sharapova claims that she did not know the drug had been banned.
Sharapova has been suspended from participating in tournaments starting from March 12.
The first hearing regarding Sharapova's case is set to take place on March 23 in London. If found guilty of deliberate use of prohibited medication she faces a 4-year ban from tennis, according to the Kommersant newspaper.