CSKA pair banned for failing dope test
"Both players' A samples revealed the presence of a prohibited substance under the category 'S6. Stimulants' from the WADA (World Anti-Doping Agency) Prohibited List 2009," UEFA said in a statement.
The two players had been provisionally suspended until the case was heard by the UEFA disciplinary committee on December 17, European football's governing body added.
The ban starts immediately, ruling them out of Tuesday's Group B match in Istanbul.
CSKA said the pair had been the victims of a procedural error by the club's medical staff.
"Our medical staff had made a technical error, failing to disclose cold medicine Sudafed during a doping test on November 3 in Manchester," the club said on their website.
CSKA said the drug taken by Ignashevich and Berezutsky had not been on a banned list but still needed to be disclosed.
CSKA will qualify for the last 16 of the Champions League if they get a better result than German champions VfL Wolfsburg, who host Manchester United in the other Group B match.