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French study: Spinal cord-injury drug detected in Tour de France riders

Experts tested hair samples from seven Tour de France cyclists with three revealing the presence of tizanidine, a muscle relaxant that is not currently banned by WADA.

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Evidence of a muscle relaxant used to treat people with multiple sclerosis and spinal cord injuries has been found in samples taken from professional cyclists, a French study found.

Hair samples were taken from seven riders during a “three-week cyclist race” in France, the report said.

The name of the team and cyclists involved are not named in the report — published in the Wiley Analytical Science Journal which was reviewed by VeloNews in full — but it would indicate that the samples were collected during the Tour de France in July.

A pathologist collected the hair samples with police in attendance and the drug tizanidine was identified in three of the seven samples collected. According to the report, tests for other substances were ordered, but have not been detailed.

Marketed under names such as Sirdalud or Zanaflex, tizanidine is not prohibited under World Anti-Doping Agency (WADA) rules.

“Tizanidine is not a WADA-prohibited drug but seems to present some interesting properties for athletes as it is a short-acting muscle relaxer,” the report said. “However, as it can cause drowsiness, it should not be used during the race but during the evening or bedtime to aid recovery. Maybe the drug can be used to avoid cramps since it has a relaxing effect on muscle. There is nothing published in the scientific literature on this specific topic.

“It is difficult to know precisely the purpose of its use because tizanidine can be used in combination with other drugs. Athletes may experience combination [sic] that they perceive as useful. Nevertheless, they have sometimes strange consumptions that look like the quest for a placebo effect rather than real evidence for an improvement of performance, particularly when a drug is not prohibited.”

The study provides a behind-the-curtains glimpse of what products some top pro racers might be using without breaking strict, anti-doping rules.

Though not banned by WADA, tizanidine can only be obtained in France through what is called a “nominative temporary use authorization”, a system designed to give people with serious or rare diseases early access to certain medications.

The drug must be ordered through hospital services, and cannot be purchased at a pharmacy.

Tizanidine works by blocking nerve impulses — pain sensation — sent to your brain. In addition to injuries, it is also sometimes used to treat opioid and alcohol withdrawal.

According to the published report — which is authored by scientists Pascal Kintz, Laurie Gheddar, and Jean-Sébastian Raul — France’s public health division within the national police requested the study. The goal was to “test for tizanidine in hair specimens collected from international athletes”.

The level of the drug found in the three positive hair samples were 1.1, 3.7, and 11.1 pg/mg.

As previous studies have not been conducted, the study said it was not yet possible to determine how much tizanidine was expected to be found in hair samples compared to the initial dose. However, it described the amounts found as “excessively low”.

The report concluded that it was “still unclear” if tizanidine could be used to enhance performance.