Epilepsy New Zealand is calling for an end to drug-switching after a fifth death was linked to a generic epilepsy drug.
On Friday an Auckland man died after switching to Logem in the past few weeks.
Logem is a generic form of lamotrigine, used to treat bipolar disorder and epilepsy.
Earlier this year, Pharmac announced it would not fund brand-name version Lamictal, forcing 11,000 people to switch to the cheaper Logem.
It hoped the cost-saving move would free up $30 million over five years, which could be spent on other drugs.
In November, Pharmac reversed its decision and allowed anyone to switch back to their original brand if their doctor recommended it.
"Pharmac and the Ministry of Health need to take responsibility for this situation and take action to ensure no further switches are made," said Epilepsy NZ chief executive officer Ross Smith.
"While investigations are being carried out by the coroner as to whether these deaths were linked to the brand change, the Ministry of Health needs to act to prevent anyone else getting switched at the pharmacy."
He says pharmacists "should be instructed to refer people back to their GP or specialist if a switch is being considered and, in the meantime, dispense their usual brand".
Last year patients taking antidepressant drug venlafaxine complained when Pharmac switched from brand-name Effexor to a cheaper version called Enlafax XR.
