A teenager who has been in an induced coma for weeks can be given medicinal marijuana, Associate Health Minister Peter Dunne has decided.

Photo: RNZ / Alexander Robertson

Nineteen-year-old Alex Renton, from Nelson, is in Wellington Hospital suffering from refractory status epilepticus, which causes him to suffer from repeated seizures.

It is not known what is causing them but it is believed his body's immune system is turning against itself.

Capital and Coast District Health Board applied to the Ministry of Health and Mr Dunne to use Elixinol, a cannabis-based product from the US which had been shown to relieve some forms of epilepsy.

Mr Dunne today said he was approving its use for Mr Renton on compassionate grounds.

"Despite the absence of clinical evidence supporting the efficacy of [the drug] in patients with Mr Renton's condition, status epilepticus, my decision relies on the dire circumstances and extreme severity of Mr Renton's individual case," Mr Dunne said.

"I have considerable sympathy for the family of Mr Renton, who face an incredibly difficult situation. Understandably they want to do the best for their son, and they believe that this option is worth trying."

Mr Dunne said he had also considered the absence of any other treatment options, the low risk of significant adverse effects, and the hospital ethics committee's recommendation.

"Ministerial approval in this case does not extend beyond Mr Renton's application and should in no way be construed as setting a wider precedent."

Mr Dunne said he was satisfied with the way the DHB and the Ministry of Health had handled the matter, and that he hoped for a good outcome for Mr Renton and his family.

Alex Renton's mother Rose told Checkpoint she was informed of the decision this afternoon just before the news was made public.

She called Mr Dunne's decision fantastic.

"Each day's a new day and today's a great day for Alex and the family," she said. "It's exciting that the minister is prepared to accept it on compassionate grounds, and that's what we were hoping for."

Ms Renton said it would take just less than a week to get the medication to Alex.