It is the latest in a series of organizations to back away from Grand Slam winner.
The world No. 2 looked rusty in his first tournament since the birth of his child.
It is a substance meant for patients with heart conditions.
Rosalyne Bachelot suggested his absence from the game in 2012 was not due to injury.
Tennis player Maria Sharapova has admitted using meldonium under a different name to treat an irregular heartbeat.
Andy Murray criticized his own sponsor for standing by Maria Sharapova.
The Spaniard also defended himself against past doping allegations.
The tennis world No. 6 faces a provisional suspension on March 12.
The American is one major behind the retired star.
Key questions about the drug the tennis star tested positive for in January.
The sportswear giant has sponsored the Russian for over a decade.
Sharapova said she tested positive for meldonium and that she did not look at a banned substances list that the World Anti-Doping Agency had sent.
Maria Sharapova has been the highest-paid female athlete in the world 10 years in a row. Here's why.