The mother of a teenager who had been in an induced coma in Wellington Hospital since early April says it is "amazing" to see her son showing signs of consciousness.

Rose Renton visited Alex early on Friday morning and saw he was opening his eyes and responding to her voice.

Renton, 19, has been in hospital since April 8 in "status epilepticus", a kind of prolonged seizure. His mother pleaded for approval to use a medicinal cannabidiol, Elixinol, after two months of attempting other treatments had failed.

Doctors were expecting to receive a dose of Elixinol, from the United States on Friday after associate health minister Peter Dunne approved the treatment for Renton on Tuesday.

Earlier this week I approved the use of a medicinal cannabis product (actually a hemp derivative) in the case of a critically ill teenager.

The decision was an unremarkable, as it was fair and obvious. To have done otherwise in the particular circumstances would have been heartless in the extreme. The public protests and the sentiments of the well-meaning worthies counted for nothing with me in this case. It was much more a matter of plain old common sense.

In the wake of that decision there have been many wrong and naïve conclusions from the enthusiasts and the antagonists that the floodgates have been opened, and that the widespread availability of medicinal cannabis of every type for all manner of aches and pains is now just around the corner. How wrong they are!

Two New Zealand specialists have entered a blazing debate on prescribing medical marijuana for pain, proving the issue continues to polarise the health sector.

Paul Hardy, Capital & Coast DHB clinical leader pain management says New Zealand doctors should prescribe medical marijuana for pain, while Auckland Regional Pain Service specialist Tipu Aamir warns against it. Their debate features in the Back to Back section of the June issue of the Journal of Primary Health Care.

Health authorities have approved the use of cannabis derived medication Elixinol - on a one-off basis - to treat a coma patient encountering ongoing seizures. But does it work?

The drug was approved on compassionate grounds by Associate Minister of Health Hon Peter Dunne, to be administered by clinicians treating Wellington patient Alex Renton.

The Science Media Centre contacted experts for comment. 

Assoc Prof Michelle Glass, Head - Department of Pharmacology, University of Auckland, comments:

A teenager in an induced coma in Wellington Hospital is the first to have received a cannabidiol product signed off by a Government minister.

On Tuesday Associate Health Minister Peter Dunne approved the one-off use of Elixinol, a cannabidiol (CBD) product from the United States for Alex Renton.

The 19-year-old Nelson man has been in hospital since early April and remains in "status epilepticus",  a kind of prolonged seizure.

Dunne said doctors have been able to apply for medicinal cannabis products for many years but this is the first time this particular avenue has been used for this particular product.

The family of Nelson teenager Alex Renton are "absolutely over the moon" to hear a Government minister has approved a cannabinoid oil to try treat his seizures.

Renton has been in an induced coma in Wellington Hospital for over two months, in status epilepticus",  a kind of prolonged seizure.

Supporters had been petitioning the Ministry of Health and staging protests in both Nelson and Wellington, calling for access to the oil.

Renton's older sister Jessie said they were relieved, shocked and "over the moon" when they heard the decision.

"We are so relieved we have been heard and action has been taken. We are grateful to the Ministry of Health and the hospital, in particular our neurologist Ian Rosemergy. Without him this wouldn't have happened."

Medicinal cannabis oil may not be enough to save the life of a Nelson teenager.

Associate health minister Peter Dunne has given one-off approval for the 19-year-old to receive cannabis oil.

Wellington Hospital staff have already tried more than 40 medications to treat Alex Renton since he was put into an induced coma two months ago.

Mr Dunne doesn't expect the oil to work, and Drug Foundation executive director Ross Bell says he's probably right.

"There is guarantee this product, because it's new, will work on this case, because it's rare."

Ross Bell says there are many other patients who may benefit from medicinal cannabis, and this case may force other cases to be reconsidered.

It finalised the application to the Ministry of Health today, although it also needs approval from the Associate Minister of Health.

In a statement, Capital and Coast District Health Board (DHB) deputy chief medical officer Dr Grant Pidgeon said Alex Renton was suffering from "refractory status epilepticus", which caused him to suffer from repeated seizures.

"It is unknown for sure what is causing his seizures but it is thought to be due to his body's immune system turning against itself, which is known as an auto-immune disorder."

Dr Pidgeon said the hospital had exhausted all standard treatment options and was now applying for approval to use a non-standard medicinal cannabinoid treatment.

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

Nineteen-year-old Alex Renton is 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 cannabidiol product from the US that had been shown to relieve some forms of epilepsy.

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

There is growing pressure on Associate Health Minister Peter Dunne to relax the rules around medicinal marijuana – but any proposed changes won't have the Prime Minister's backing.

Nineteen-year-old Alex Renton has been in an induced coma at Wellington Hospital for more than a month, and his doctor and parents believe cannabinoid oil could improve his condition.

Protestors turned out yesterday to urge Mr Dunne to sign off on it in Wellington and Nelson, including Labour's West Coast MP Damien O'Connor.

Council of Trade Unions president Helen Kelly, who was recently diagnosed with lung cancer, says it's unfair to string families along.