Maria Sharapova has been provisionally banned from tennis after she revealed on Monday she tested positive for a recently banned drug that she has been taking for 10 years for health reasons.

Nike and other companies are suspending major endorsement deals with Russian tennis star Maria Sharapova after she admitted failing the drug test at this year’s Australian Open.

The drug is called meldonium, though Sharapova said she had been using it under the name of mildronate and was unaware of both the different name and the fact it is on the World Anti-Doping Agency’s banned list until she received a letter notifying her. of the positive test 10 days ago.

Sharapova claimed she was prescribed meldonium by her doctor in 2006 to deal with health issues such as an irregular heartbeat and a history of diabetes in her family. But the substance was added to the banned list in January of this year because Wada said there was “evidence of its use by athletes with the intention of enhancing performance”.