Former World No 1 tennis player Maria Sharapova on Monday announced that she had tested positive for banned drug meldonium before the Australian Open in January this year. The 28-year-old has been provisionally suspended starting March 12, and the International Tennis Federation is expected to confirm further action later. Soon after her announcement, sport apparel major Nike said it has suspended its relationship with Sharapova. Swiss watch manufacturer Tag Heuer and luxury carmaker Porsche also terminated their contracts following the revelation.

In a press conference, Sharapova admitted to failing the test and said she took “full responsibility for it”. She claimed she has been taking a drug called mildronate for the past 10 years, prescribed by her family doctor, for health issues including a magnesium deficiency, an irregular heartbeat and a family history of diabetes.

A few days ago, she received a letter saying the drug mildronate is also called meldonium, and is on the World Anti-Doping Agency’s list of banned substances for being linked to performance enhancement. Sharapova claimed she did not know this and had been taking the drug legally since 2006.

WADA has said it will not comment on the case until the ITF makes its decision clear. Sharapova’s lawyer believes they can appeal on mitigating circumstances and have the sanctions against her reduced.

Women’s Tennis Association CEO Steve Simon said, “Maria is a leader and I have always known her to be a woman of great integrity. Nevertheless…it is every player's responsibility to know what they put in their body and to know if it is permissible. The WTA will support the decisions reached through [the Tennis Anti-Doping Program’s] process.”