A staff nurse who was employed at the Royal Hospital in Donnybrook, Dublin, has been found guilty of professional misconduct, on six counts, by a nursing board inquiry.
John de Lara was found to have the illegal drug crystal methamphetamine in his possession and had also ordered the decongestant, Sudafed, from the hospital under other staff members' names.
A decision on any sanction will be made at a later stage.
Earlier, the inquiry heard from a care assistant at the hospital that he was "shocked and surprised" to learn that Mr de Lara had ordered Sudafed from the pharmacy in his name, without his permission.
Nicholas Mallari said he did not give Mr de Lara permission to order the drug in his name.
Mr Mallari described Mr de Lara as a good nurse.
The inquiry heard that Sudafed can be used to make illegal drug crystal meth.
Lawyers for Mr de Lara have said he ordered the Sudafed to send it home to his family in the Philippines.
Mr de Lara worked at the hospital from 2003 to November 2014.