What is trimetazidine and how does it impact sport?
World number two Iga Swiatek has won five Grand Slam titles
- Published
It’s not the first time that the drug trimetazidine, or TMZ, has caused controversy in sport.
But the news that five-time tennis Grand Slam champion Iga Swiatek has been suspended after consuming medication contaminated by TMZ has put the substance in the spotlight again.
What is TMZ and how could it improve sport performance?
Trimetazidine is a medication usually taken to treat heart-related conditions.
It is commonly used to treat problems such as angina - a chest pain caused by reduced blood flow to the heart.
TMZ both increases blood flow to the heart and stimulates the metabolism of glucose, which can improve endurance, which is why it is a banned substance in elite sport.
Who decides which drugs are on the banned list?
The World Anti-Doping Agency (Wada) is the international body that coordinates anti-doping rules and policies across sport.
Wada publishes a List of Prohibited Substances and Methods, external which is updated annually.
Trimetazidine is listed as a 'metabolic modulator'. These drugs make your heart work more efficiently, without having any large impact on your blood pressure or heart rate.
Wada prohibits the use of TMZ both in or out of competition. It is usually detected in urine samples.
Another of those metabolic modulators is meldonium, which five-time Grand Slam winner Maria Sharapova tested positive for and was subsequently banned from tennis for 15 months.
Have any athletes tested positive for TMZ before?
Yes. TMZ has been at the centre of several high-profile doping cases.
Russian figure skater Kamila Valieva was given a four-year ban by the Court of Arbitration for Sport earlier this year, after testing positive for TMZ in a sample collected before she competed at the 2022 Winter Olympics.
Then, at just 15 years old, Valieva was part of Russia’s figure skating team who had finished first in the team event. Earlier this year, the International Skating Union (ISU) dropped Russia from gold to the bronze medal following her doping ban.
Kamila Valieva tested positive for the banned heart medication TMZ in December 2021
Twenty-three Chinese swimmers also tested positive for TMZ before the Tokyo Olympics in 2021. They were cleared to compete in the Games after China’s own anti-doping agency found the results were caused by contamination.
Wada had concluded it was "not in a position to disprove the possibility that contamination was the source of TMZ", but has since launched a review into the failed tests.
How have athletes consumed TMZ?
In many cases athletes are found to have consumed TMZ unintentionally, through contamination.
Valieva claimed her positive test result could have been caused by consuming food that had been prepared on a chopping board used by her grandfather to crush his pills.
However, the Court of Arbitration for Sport said they could not back up that claim with "any concrete evidence".
Tennis world number two Swiatek tested positive for TMZ in a urine sample collected in August 2024.
She was provisionally suspended from 12 September before winning an appeal. Swiatek will now be eligible to play from 4 December 2024.
After an investigation, the International Tennis Integrity Agency (ITIA) accepted that the positive test was caused by the contamination of a regulated non-prescription medication, melatonin, which she was taking for jet lag and sleep issues.