Former world's number one tennis player Maria Sharapova announced Monday that she tested positive for meldonium at the Australian Open. The said drug was added to the World Anti-Doping Agency's (WADA) banned list only this year.

Sharapova took the test on Jan. 26, a day after she lost the quarterfinal match to rival Serena Williams, and was confirmed by the Tennis Anti-Doping Program. According to The New York Times, the five-time Grand Slam champion, who has taken some time off from the sport due to a forearm injury, will be suspended provisionally during the pendency of the doping case.

The 28-year-old Russian athlete started using meldonium 10 years ago as a treatment for various medical issues. 

NBC News reported that meldonium improves the blood flow and was a cardiac drug regularly prescribed to Soviet troops when they fought in Afghanistan in the 1980s.

Ivars Kalvins, the creator of meldonium, said in a previous interview that Soviet soldiers were given meldonium to keep up with tough conditions during the war such as high altitudes and oxygen deprivation.

"If they have to run 20 kilometers with all the gear, at the end they would get ischemia (a blood circulation condition)," Kalvins said, illustrating the necessity of the drug for the military.

Kalvins, who was a finalist for the European Inventor Award in 2015 for his work on meldonium, explained that the drug is not "doping" since it allows users to "withstand more physical pressure, but the body still spends its spare reserves."

Sharapova explained that she resorted to meldonium intake in the last decade to treat various health problems including early signs of diabetes and "irregular" echocardiography exam results. Her lawyer, Atty. John J. Haggerty, clarified that she did not use meldonium every day for 10 years.

"Maria at all times took the mildronate in accordance with the recommendations of her doctor," Haggerty said, as quoted by ESPN.

The WADA banned the drug because it improves oxygen uptake and boosts endurance. Many athletes have been caught using the drug illegally since Jan. 1 this year.

Haggerty, however, reiterated that "the dosage that Maria was taking was substantially less than any dosage that has been linked to potential performance-enhancing attributes."

Other athletes who reportedly failed the drug test are Swedish runner Abeba Aregawi and Russian ice dancer Ekaterina Bobrova.

"I made a huge mistake, and I've let my fans down. I've let this sport down that I have been playing since the age of 4 and that I love so deeply," Sharapova said in a press conference.

Haggerty said he would request a minimum penalty from the International Tennis Federation since Sharapova was taking a doctor-prescribed dose for health purposes.