The Court of Arbitration for Sport has cleared Alexandr Kolobnev of doping at the 2011 Tour de France, and rejected the International Cycling Union’s request to ban the Russian rider for two years.

The court ruled on Wednesday that Kolobnev’s positive test for the diuretic Hydrochlorothiazide after the fifth stage was “justified by medical reasons totally unrelated to sport performance”.

“The CAS panel found that Kolobnev has been suffering from varix dilatation, a chronic vascular disease, for 15 years,” the court said in a statement.

World sport’s highest court upheld a Russian anti-doping tribunal verdict which issued Kolobnev with a reprimand and fine of 1500 Swiss francs ($A1545).

The UCI had appealed to the court for a two-year ban and fine of 350,000 euros ($A440,000) for the 2008 Beijing Olympics road race bronze medallist.

“We accept and respect all CAS decisions. They confirmed the stance of the national federation,” UCI spokesman Enrico Carpani told The Associated Press.

Diuretics such as HCT can hide the presence of other banned substances, but anti-doping rules allow athletes to prove they did not intend to consume it or enhance their performance.

CAS accepted Kolobnev’s defence that he had taken the drug in a product “to supplement the treatment for vascular disease”.

The rider was able to show the court that he bought an over-the-counter medication in Russia two weeks before the race, and had it with him in France.

Kolobnev’s positive test was the only anti-doping case opened following the 2011 Tour.

His Russian team Katusha withdrew him before the 10th stage and later dropped him for the 2012 season.

The 30-year-old Kolobnev is also a two-time runner-up in the world championships road race.