People with epilepsy are being warned to check for changes after the switch-up of a widely used brand of medication.
Pharmac is switching from Lamictal to Logem from Tuesday, in what's seen as a cost reduction move.
But Epilepsy New Zealand President Dr Peter Bergin says this could cause unnecessary anxiety.
"There shouldn't be any difference, but people don't need to have a big change in the dose or amount that gets into the blood to have a seizure."
Pharmac says it gathered expert advice before making the change, and both brands have the same active ingredient.
Neurologists say a trial should be undertaken to make sure one drug isn't more effective than the other.
Dr Bergin says they're setting up a register.
"We hope that not many people have problems, but certainly if there are we want to know about them so we'll be able to go back to the Ministry of Health or Pharmac and tell them that it was a bigger problem than had been anticipated."
Pharmac says it wouldn't have made the switch if clinical advisors said it wasn't appropriate.
"If it turned out that one of the drugs was more effective and controlling the seizures or produced fewer side effects, that would be important to know," says Dr Bergin. "That study wouldn't be particularly difficult to run."
Pharmac says Logem is delivered to the body in the same way as Lamictal.
"This means it will have the same effect as the other brands," it said in a statement.
"Before deciding to change the funding arrangements for this medicine we got expert advice from healthcare professionals who work directly with people with epilepsy and people with mental health conditions to make sure it would be appropriate for people to change brands of lamotrigine."
Pharmac chief executive Lisa Williams told RNZ they have learned from previous brand changes that some people may need to stay on the original medication.
"People who have experienced problems changing, their doctors can make an application on an easy form to Pharmac so that we can assess whether or not ongoing funding of the previous brand should be made available.
"We can also accept applications for people where their GPs think it's not going to be possible for them to change."
When Pharmac switched from antidepressant Effexor to a generic version of venlafaxine two years ago, some patients reported ill-effects.
Effexor costs about $55 a month for anyone wanting to buy it themselves. Data showed between June and November 2017, there were more than 110 reports of adverse reactions - compared to just nine over the same period in 2016, when Effexor was funded, NMZE reported.
This is despite the two drugs supposedly being identical.
Newshub.
