The fallout from Maria Sharapova’s failed drug test has ensnared her native Russia as it becomes clear that the banned substance found in her system is creating wider problems for Russian sports.

Sharapova, a five-time Grand Slam winner, announced Monday that she had tested positive for meldonium during the Australian Open in January, shocking the tennis world and prompting a swift response by a number of her sponsors.

Few in the Los Angeles hotel conference room with Sharapova on Monday probably recognized the name of the drug, but in Russia, meldonium, also known as mildronate, was a common treatment for athletes before it was added to the World Anti-Doping Agency’s prohibited list in January.

The new ban is causing far-reaching troubles for the Russian sporting establishment, which is already reeling from an international track and field suspension over accusations the country conducted a massive doping program.

On Wednesday, a spokesman for the Kremlin said Sharapova’s failed drug test “should not be projected onto” Russian sports generally. But even as the Kremlin sought to play down Sharapova’s lapse as an individual case, more Russian athletes were drawn into the controversy.

In the two days since Sharapova’s announcement, seven Russian athletes have been confirmed as having tested positive for meldonium. Among those provisionally suspended are an Olympic gold medalist in short-track speedskating, Semion Elistratov, and his teammate, the world champion Pavel Kulizhnikov.

Russia’s sports minister, Vitaly Mutko, has warned that more positive tests for meldonium are likely to come. Athletes from Sweden, Ethiopia and Ukraine have also reportedly tested positive for meldonium this year.

The surge in positive tests has been linked to the larger Russian doping scandal, but it also seems to reflect a clash of understanding about meldonium between Russian trainers and WADA, the antidoping body.

In January, WADA included meldonium on its list of hormone and metabolic modulators. The decision to ban the drug has been met with bafflement and anger among top Russian athletes and sports physicians. They said that they did not understand why the drug, legal for decades but monitored by WADA for at least a year, had been outlawed and that they did not believe that using it constituted doping.

Until the fall, Russian teams had used the drug regularly and openly, viewing it as a remedy for fending off exhaustion and heart problems. Most team coaches would keep a supply, administering it along with other standard vitamins.

“I’ve been working for 20 years; we could never imagine that it would be included as a doping substance,” said Sergei Sheremetiev, a physician with Russia’s ski-jumping team.

Created as a treatment for heart conditions in 1975, meldonium is widely available from Russian pharmacies without a prescription, selling for $3 to $10 for about 40 capsules. It can also be purchased online. Meldonium is not approved by the Food and Drug Administration for sale in the United States, where Sharapova has been based since she was 7. The Russian tennis federation said its doctors had not known she was taking meldonium.

Meldonium helps increase blood flow and therefore increases the amount of oxygen taken into the body, which would allow athletes to recover faster while training. The drug’s inventor, Ivars Kalvins, a professor at Latvia’s Institute of Organic Synthesis, said in a 2009 newspaper interview that the drug was once used by Soviet soldiers lugging heavy equipment at high altitudes during the invasion of Afghanistan.

On its website, Grindeks, the Latvian company that is the main supplier of the drug, said that in addition to its use for cardiovascular disease, the medication was used “for the improvement of work capacity of healthy people at physical and mental overloads and during rehabilitation period.”

Sheremetiev said: “It’s a good drug. Until they banned it, we used it in many types of sport: hockey, skiing — in those where there’s pretty serious strain.”

Grindeks said in a statement that it did not believe meldonium should be banned for use by athletes because it “cannot improve athletic performance but it can stop tissue damage in the case of ischemia,” which is the lack of blood flow to the heart.

Until the ban, Sheremetiev said, he had given the drug to his own athletes about twice a year.

Sharapova and her lawyers said she was prescribed meldonium by her family doctor in 2006 for a variety of health problems, including signs of diabetes, irregular EKG readings, magnesium deficiency and frequent cases of the flu. She said she had failed to read an email sent by WADA that confirmed the medication had been added to the prohibited list for 2016.

The Russian trainers and officials said they were obeying the ban on meldonium, but they insisted the drug — despite its benefits — should not be considered a performance enhancer. Sheremetiev and other team physicians said it was merely for restoring physical fitness. But WADA has disagreed. The body’s president, Craig Reedie, in an open letter to The Independent, wrote that meldonium was “a big concern because it’s clear that people are abusing the drug.”

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Several studies in the past year have bolstered WADA’s case. A 2015 study, funded in part by the Partnership for Clean Competition, analyzed 8,300 urine samples collected at doping control sessions and found that 182 (2.2 percent) contained the substance. A study of last year’s European Games in Baku, Azerbaijan, published Wednesday in the British Journal of Sports Medicine, found an “alarmingly high prevalence of meldonium use by athletes.” According to the study, 13 winners or medalists were taking meldonium, and 66 athletes tested positive for it.

Growth in the use of meldonium, particularly among Eastern European athletes, was a subject of the latest documentary from the German network ARD, which first reported on systematic Russian doping in 2014. The investigation cited a 2015 Russian study that found meldonium in 17 percent of 4,316 urine samples tested.

Still, Mark Stuart, a London pharmacist who is on the medical and antidoping commission of the European Olympic Committees, said the evidence around whether the drug enhanced performance was “quite thin.”

Still, the fact that so many athletes were using it suggests that they believed it improved performance, he said, adding, “I can’t see how so many athletes — young, quite fit and healthy — would really have a need for this particular drug.”

Russian physicians acknowledged that they had received plenty of notice to stop their athletes from using meldonium. National teams stopped treating their athletes with the drug in September, officials said, after WADA warned the drug would be banned beginning in January. Some federations said they had destroyed their supplies of the drug.

Sheremetiev and a number of other federation officials and trainers said that, given the warnings, it was incomprehensible that top athletes had continued to take meldonium.

Russia’s national speedskating team appeared to have been hit particularly badly by the new ban. Three of its athletes tested positive, including Elistratov, a world-record holder.

At a news conference in Moscow, the speedskating federation’s president, Aleksey Kravtsov, insisted that none of his athletes had taken the drug knowingly and that the team’s trainers had been told not to administer it. Kravtsov said the federation had evidence to prove it and would be appealing its athletes’ suspensions.