Tramadol is a synthetic opiate, which has a lower side-effect profile than Morphine, and causes less nausea, respiratory depression and sedation.
Because Tramadol affected the central nervous system it would alter a user's mental state, the tribunal said.
An investigation by the hospital was launched when discrepancies in the number of tablets was discovered. The inquiry resulted in Ms Hattaway being fired on September 27.
Ms Hattaway told the tribunal it was "simply bad practice'' that led her into appearing before them.
She said she used to carry medication in her pocket; Panadol, Tramadol and asthma treatment medication, to dispense to patients who had been prescribed the drugs.
She would enter the name of a patient whose chart she happened to have on hand whilst at the Pyxis machine and accessed the drug, put it in her pocket and disposed of it at the end of the day if not used, she said.
But the tribunal said, while there was no evidence that Ms Hattaway was using the drugs for herself, her explanation of accessing the medication for patients seemed "highly implausible''.
"The conclusion that the tribunal have drawn from the evidence before it is that Ms Hattaway intended to access Tramadol for purposes other than giving it to patients.''
The tribunal put Ms Hattaway on notice by suspending her from practice for six months, but that suspension would only be enforced if she failed to organise a supervisor and enrol in nursing courses within three months.
The tribunal also ordered her to pay $5000 in costs.
