Jockey Kevin Sexton has been handed a two-year suspension following a a positive drugs test.
The former champion conditional's ban is set to begin on November 21, with the final 18 months deferred providing he does not test positive again during that period.
During his suspension, Sexton will be randomly tested by the Irish Turf Club's senior medical officer, Adrian McGoldrick.
Sexton won the 2014 Troytown Chase at at Navan aboard Gordon Elliott's Balbriggan and has been riding regularly for the leading trainer in recent weeks.
Danny Grant is also set to serve a lengthy suspension after testing positive for a metabolite of cocaine.
Grant was suspended in 2010 and 2014 for the same offence.
It was discovered that the source of the failed drugs test was a herbal tea product called Mate De Coca, which the jockey had bought online.
The teabags, bought to help soothe a long-standing skin condition, were consequently sent to the Turf Club for testing and indicated the presence of cocaine.
A Turf Club statement read: "Danny Grant accepts he is in breach of Rule 277(I). As he was stood down from September 2, 2016, the commencement date for the suspension is this date.
"The 18 months suspended penalty from 2014 commences on this date and ends on March 2, 2018.
"In addition a further penalty of three years was imposed to run concurrently from September 2, 2016 for the two rule breaches dealt with today.
"However, Danny can make application to the Referrals Committee at any time after March 2, 2018 to lift the suspension.
"The source of the cocaine metabolite was accepted as the Mate De Coca tea which Danny had to recommence taking to aid his skin condition."