The Colombian was retroactively disqualified from this year's Tour de France - where he finished sixth in the general classification - after two blood samples came back positive for tramadol.

The painkiller is not currently outlawed by the World Anti-Doping Agency - that will be the case from 2024 - but in-competition use is prohibited by the UCI.

After being disqualified, Quintana appealed to the CAS but the Swiss-based court has dismissed his petition.

It is within the UCI's power and jurisdiction to outlaw tramadol for medical reasons, the CAS ruled.

It was also convinced by the evidence indicating Quintana's samples contained tramadol and its two metabolites.

The UCI welcomed the decision and said it "reinforces the validity of the tramadol ban".

Tramadol is a powerful opioid painkiller.

Tramadol abuse in sport is a concern as it can lead to physical dependence on the substance and opiate addiction.

The UCI tests for tramadol using dried blood spots.

A first offence is punishable by disqualification from the relevant event and a second infringement brings about a ban of five months.

Quintana's offence was his first, so he has not been suspended by the UCI.

Quintana has been one of the leading road cyclists of last decade, winning the Giro d'Italia in 2014 and the Vuelta a España in 2016.

The 32-year-old is without a team at present.