Since new Russian legislation was introduced in June 2016, medication containing certain strong or poisonous substances must be declared to the Russian Customs Services when you enter the country. All the drugs are listed on the Rossiyskaya Gazeta website (in Russian). The British Embassy is in contact with the Russian government to get an English language version of the list. The Russian government has confirmed that the new legislation doesn’t apply to medication used for colds, flu, anti-inflammatory drugs, or to treat gastrointestinal diseases.
Since the introduction of the legislation, the British Embassy is not aware of any British nationals having medicines scrutinised or withheld when entering the Russian Federation. However, if you intend to travel to Russia with any medication on the list, it must be accompanied by a prescription in the traveller’s name which has been translated into Russian, and then notarised (notarisation services in the UK are available from a Notary Public).
If you’re not sure whether you need a prescription and notarised translation to bring your medicines into the country, you should check with the Russian Embassy in London or Consulate General in Edinburgh.