The Latvian manufacturers of meldonium must be rubbing their hands with glee over the furore around its use by Russian tennis ace Maria Sharapova, who admitted on Monday that she had tested positive for the substance at this year’s Australian Open.

A Russian supplement website told BBC Sport it had seen a spike in sales since Sharapova’s revelation that she’d been given Mildronate (also known as meldonium) by a family doctor for 10 years.

Although she said she’d been taking it legally for health reasons since 2006, the World Anti-Doping Agency (Wada) banned the drug on January 1 this year and as a result Sharapova could face a four-year ban from tennis.

Several other athletes have reportedly tested positive for meldonium since the start of the year, including Russian ice dancer Ekaterina Bobrova, but what is it, and what should it be used for?

What is meldonium?

Meldonium is a cardiac drug developed in Latvia in the early 2000s which is only distributed in the Baltic countries and Russia.

It’s not licensed in the UK, so although you can import it for personal use - although that’s not recommended – it is illegal to sell it here.

No negative side effects have been reported, although one Latvian manufacturer said it’s possible people may suffer headaches and agitation and, rarely, skin irritation.

[Read more: How to pay much less for your drugs and medicines]

What does meldonium treat?

Ischaemia

This is a condition where there is not enough blood flow to an organ, usually because of a blocked artery. Where blood flow is blocked to the heart, ischaemia can cause angina and heart attack. Blockages to arteries in the brain can cause stroke. Meldonium apparently helps to clear up fat build-up in the arteries.

Diabetes

Sheffield Hallam University lecturer in forensic science, Dr Tom Bassindale, told the BBC that in addition to clearing fat from arteries, the drug also has the ability to alter the way the body uses energy, by stimulating glucose metabolism. Sharapova reportedly has a family history of diabetes as well as a magnesium deficiency. She started taking the drug because she was regularly falling ill.

Why are athletes taking it?

Because meldonium increases blood flow, the taker’s blood carries more oxygen to the muscles, which could improve an athlete’s stamina and endurance. It could even have mental benefits, according to Dr Bassindale.

“It’s advertised as giving a mental focus, removing external stress, so you feel sharper,” he told the BBC.

“There is a slight central nervous system effect, like with stimulants such as caffeine, which gives you a sharper edge.

“It will aid recovery quicker from a hard effort. There is also an endurance effect,” he added.