The Scottish Government has stepped up calls for a "legal high" drug to be outlawed after the deaths of the two teenagers.
Mephedrone, commonly known as `bubbles`, had been taken by Louis Wainwright, 18, and Nicholas Smith, 19, before they died in Scunthorpe, Yorkshire, on Monday.
Community Safety Minister Fergus Ewing said the UK Government, which has responsibility for banning or reclassifying drugs, must be ready to act quickly, with mephedrone also linked to the death of a woman in Scotland this year.