Caution urged over cannabis for paediatric epilepsy

Two trials have shown medical cannabis has a modest effect for paediatric epilepsy, but it did not work for the majority of the patients

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Scientific trials on the use of medical cannabis in severe paediatric epilepsy have shown modest but encouraging results – but far short of the miracle claims circulating in the community.

Dr John Lawson, a paediatric neurologist at Sydney Children’s Hospital, says clinicians would be wrong to dismiss anecdotal reports about the benefits of medicinal cannabis.

“I think it would be naïve to ignore completely the anecdotal evidence,” he told The Medical Republic in an interview.

“That anecdotal evidence has led us to this point.  Families are taking risks and trying this. They are ahead of medicine and the law in that way.

“It would be arrogant to dismiss that completely.”

Professor Lawson, co-author of a narrative review on cannabidiol in treatment epilepsy in children in the current issue of the MJA, said the science was only now emerging.

“The first double-blind randomised controlled trial was published in May 2017.  The second one was published about a week ago,” he said.

“Both trials showed it had a modest effect, but it did not work for the majority of the  patients in the trials.”

The trials – conducted in north America and Europe on children with severe drug-resistant epilepsy – showed “encouraging results” but did not justify the claims circulating in the community by those pressing for access to medical cannabis.

“It did help a proportion, and the benefit overall was modest, meaning about a 20-30% reduction in seizures.  If you were having 20 fits a day, and you are (now) having 15 a day,  well there’s no miracle there.  Really, your life may not be much better.

“These trials show there is some truth, that these compounds have a benefit – but not a miracle.”

The other side of the argument against regulated access – that medicinal cannabis is a natural substance and has been used for thousand of years – overlooked evidence of adverse effects, Dr Lawson said.

The two trials showed very clearly that there were significant adverse events, which led to children being withdrawn from the program, he said.

“At least a third get excessively sleepy.  There are GI side effects – diarrhoea, vomiting, significant weight loss – and that led in both trials to a 10-20% withdrawal. They didn’t want to take it any more.”

In the MJA review, Dr Lawson and colleagues write that parents are frequently raising the possibility of prescription cannabidiol, a Schedule-4 drug in most states, for children with drug-resistant epilepsy.

The paper outlines the legal prescription pathways via the TGA’s Special Access Scheme and Approved Prescriber provisions.

For paediatric epilepsy patients, in practice, general practitioners and paediatricians can only apply to the SAS with support from a paediatric neurologist, it says.

It is no secret, however, that many Australian families, carers and patients are turning to the black market or product obtained overseas because they are convinced medicinal cannabis can work for them.

The  review authors call for more controlled research and less hype from the media and politicians.

Generally, they call for a balance between compassion and careful assessment for patients who might benefit from medicinal cannabis.

“It is too early to form conclusions, and there are risks associated with liberalising access in the absence if standard regulatory requirements demonstrating quality, safety and efficacy.

“Supporting patients to take an active part in their care requires us to provide them with providing evidence-based information about the treatment options available.”

MJA; 19 February