More than 100 athletes have tested positive for meldonium already in 2016

Since it was banned on January 1, 2016, more than 100 athletes around the world have tested positive for meldonium.

While tennis player Maria Sharapova is the most high profile athlete to fall foul of the new drug laws, dozens of other athletes from a host of sports have also been caught out.

On March 11, the World Anti-Doping Agency (WADA) announced that 99 athletes had failed tests for the drug, which is used to treat heart conditions, with four more positives announced on Monday.

Monday's revelations bring the total number of Russian athletes banned for the drug up to 16, including Sharapova, speed skating Olympic gold-medallist Semion Elistratov and Katusha cyclist Eduard Vorganov.

Sharapova took the surprising step to announce a press conference to reveal that she had tested positive for meldonium, stating that she had been prescribed the drug by her family doctor for years. She then claimed not to have seen that the drug had been banned by WADA on January 1.

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But ignorance and naivity cannot be behind all of the positive tests. The BBC's Matt Slater tweeted on Monday that the Latvian manufacturer of meldonium, Grindeks, say the drug takes "several months" to leave your system, which, if true, could explain the high number of positives.

Some people are also questioning why the drug has been banned in the first place, with its performance-enhancing nature not fully clear.

But a WADA spokesman said the banned substance list "is updated annually and with a full and thorough consultation period with experts and stakeholders."

"A substance or method may be added to the list of it meets two of the following three criteria: enhances performance; detrimental to the health of the athlete; contrary to the spirit of sport."

Many of the athletes who have tested positive remain anonymous because their cases are still be adjudicated on, but at the current rate the number will rise well above 100 in the coming weeks and months.