Peru striker Paolo Guerrero's final appeal against a 14-month ban has been rejected by a panel of five Swiss federal judges.
The decision brings the long-running case to a close and provides confirmation that Guerrero will not be able to make his return until early next month.
It means he will miss Peru's friendlies against Paraguay and El Salvador in the United States this month.
Guerrero was cleared to play at last year's World Cup, where Peru made their first appearance at the tournament for 36 years, after he successfully argued he had ingested a banned substance accidentally.
The 14-month ban was originally announced when the 34-year-old tested positive for cocaine metabolite bezoylecgonine after his country’s 0-0 draw with Argentina in Buenos Aires in October 2017.
It meant he would be banned from captaining Peru at the World Cup but his ban was frozen following an appeal at the Swiss Federal Tribunal.
It was claimed Guerrero had not intentionally committed the offence and decided he would suffer if he missed the event which would be "the crowning achievement" of his career.
The 34-year-old insisted had he ingested the banned substance by accident through an aromatic tea made from coca leaves.
The striker’s ban was re-introduced following the conclusion of the World Cup, a decision which he then appealed.
This was turned down in October and Guerrero, who plays his club football for Brazilian side Internacional, has now exhausted all of his appeals against FIFA and the World Anti-Doping Agency (WADA).
Switzerland's supreme court confirmed the latest appeal had been rejected, while the panel also ordered Guerrero to pay court costs of CHF7,000 (£5,300/$6,970), and CHF8,000 (£6,100/$7,960) to WADA.
Guerrero signed a three-year contract at Internacional in August but is yet to play for them due to the suspension.