The man, Christopher Wilson (27), was dispensed someone else's methadone on March 16, 2006, and died later that day from an overdose.
In an appendix to the report, Ms Lamb's expert adviser, pharmacist Maree Jensen, noted her investigations had led her to the view that Mr Barron had also breached two principles of the Pharmacy Council's Pharmacist Code of Ethics, namely to optimise medicines related outcomes and prevent harm to the patient and public.
Chief executive Bronwyn Clark said the council would take some time to consider Ms Lamb's findings.
It hoped to have a response to the report by the end of next week.