West, who competes for the QMMF Racing Team in the feeder class to MotoGP, tested positive for the stimulant Methylhexaneamine which is prohibited in competition, an infringement of the 2012 FIM Anti-Doping Code.
The test was taken at the French round of the Moto2 series at Le Mans on May 20 and West forfeits the seventh place finish he recorded in that race.
West, a 250cc GP winner in Holland in 2003, also drops out of the top 15 positions in the overall points standings as a result.
West finished second at his home round at Phillip Island on October 28, two days before the suspension was confirmed by the FIM.
The FIM has given West five days from October 30 to appeal but if he chooses not to or such a move fails the ban will rule him out of the final round of the series at Valencia on November 11.