Ireland's Denis Lynch has been banned for three months and fined €1,142 by world equestrian body the FEI.
Lynch was automatically suspended at the Olympics in August following a positive medication test on his horse Lantinus.
The ban is backdated to August 21 and will run until November 21. Lynch has also been ordered to pay €1,305 towards the costs incurred in hearing his case.
Horse Sport Ireland boss Joe Walsh said that the group established by the Board of Horse Sport Ireland to advise on the eradication of banned substances from the sport in Ireland "would take the details of the FEI decision into account when issuing their recommendations to the board".