Russia had already lost their 2008 4x400m relay silver.
The other three are weightlifters Tigran Martirosyan, Alexandru Dudoglo and Intigam Zairov.
They hail from Armenia, Moldova and Azerbaijan respectively.
The IOC carried out more than 4,500 drugs tests at the 2008 Olympics but only nine athletes tested positive.
It has since retested more than 450 samples, using new methods to uncover banned substances which would have gone undetected at the time.
The IOC has also carried out about 250 retests on samples from London 2012.
Russian track and field athletes were banned from competing at Rio 2016 by the IAAF after widespread, state-sponsored doping was uncovered in the country.
