Sportspeople will die in action as a result of being denied meldonium, according to the heart drug's inventor.
On Monday, five-time Grand Slam champion Maria Sharapova announced she had tested positive for the drug.
Meldonium, also known as mildronate, was developed to treat diabetes and various heart-related diseases but was banned by the World Anti-Doping Agency (Wada) in January.
"We will see many deaths on the field," Ivars Calvins told BBC Radio 5 live.
"Athletes who use mildronate will not be able to do it in the future and will be not more protected."
The Latvian added: "This drug was on the market for 32 years - as a self-protective agent - and now suddenly it becomes forbidden.
"You could see a sudden death in the sports events sometimes."
World number seven Sharapova said she has been taking the drug since 2006 for health reasons.
The 28-year-old Russian, who said she was unaware meldonium was added to Wada's list of banned substances on 1 January, failed a drugs test at the Australia Open later that month.
Sharapova, the highest-paid female athlete in the world in 2015, could be banned for as many as four years.
Meldonium also has the ability to adjust the body's use of energy, stimulating glucose metabolism and also helping to clear fatty build-up in the arteries - and could also have a positive effect on stamina and endurance in athletes.
Several athletes has tested positive for it in 2016, including 1500m world champion Abeba Aregawi, 2015 Tokyo Marathon winner Endeshaw Negesse and Russian ice dancer Ekaterina Bobrova.
Thirteen medallists from the 2015 European Games in Baku were also found to have been taking meldonium.
"As far as I'm concerned, the system works," former Wada president Sir Craig Reedie told BBC Sport.
"There is research on a drug, there is monitoring on a drug, there is information given to the athletes that it will come on to the prohibited list on a set date.
"I can't believe [there can be any excuse]."
UK Anti-Doping CEO Nicole Sapstead said she could not rule out a British athlete testing positive for meldonium.
"I will never say I'm confident about anything, because the nature of anti-doping is so unpredictable," she said.
"There's always a danger that when a new substance is introduced onto the prohibited list that athletes will be caught out. We'll just have to wait and see."