Sales of the doping drug meldonium have more than doubled in Russia since the nation's tennis star, Maria Sharapova, admitted to taking the substance, a survey has revealed.

Key points: Pharmaceutical outlets more than twice as much meldonium than a week ago

Pharmaceutical outlets more than twice as much meldonium than a week ago Drug treats lack of blood flow to parts of body

Drug treats lack of blood flow to parts of body DSM Group's chief says scandal was good advertising boost for drug

Russian pharmaceutical outlets sold 78,300 boxes of meldonium between March 7 and 13, 220 per cent more than in the previous week, according to a survey by DSM Group, which tracks the pharmaceutical sector.

The Soviet-era drug was thrust into the spotlight on March 7, when Sharapova said she had tested positive at the Australian Open.

Sharapova maintained she took it for health reasons, not as a performance enhancer, and was unaware it had been banned by doping watchdogs.

The drug, manufactured in Latvia, dates from the Soviet Union in the 1970s. It is used to treat ischaemia — a lack of blood flow to parts of the body.

The increase in blood flow it produces could improve endurance and recovery time after exercise.

"The doping scandal was a very good advertising boost for meldonium, enabling it to be introduced to a much broader public," DSM Group's chief executive, Sergei Shulyak, said in a statement.

"People felt that if Sharapova used the medication, that meant it really helped."

Mr Shulyak said patients fearing that demand for the drug would cause its price to rocket had also been stockpiling the medicine.

The World Anti-Doping Agency (WADA) said on March 11 it had recorded 99 positive tests for meldonium since January 1.

WADA moved meldonium from its "monitored" to "prohibited" list at the start of 2016 "because of evidence of its use by athletes with the intention of enhancing performance".

AFP