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Neurologists suggests guidelines for safe use of medicinal cannabis

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The National Clinical Programme for Epilepsy (NCPE) aims is to improve the delivery of epilepsy care to all patients in Ireland through improved access to care in the community and the provision of expert care in designated centres for those who need it. This statement is being made on behalf of the Clinical Advisory Group of the NCPE under the governance of the Royal College of Physicians in Ireland which consists of neurologists with a special interest in epilepsy as well as a range of other professionals, neurophysiologists, nurses, technicians and scientists interested in epilepsy.

As healthcare practitioners with a special interest in epilepsy we aim to provide comprehensive, evidence-based and safe care for all our patients. We are very mindful of the impact on adults, children and their families of the diagnosis of many of the serious neurological conditions we encounter. We aim to support our patients and their families through the range of available treatments. We fully recognize the devastating effects of severe epilepsy on children and adults and understand the desperation felt by families to help their loved-ones.

The recent interest in the use of cannabinoid derivatives to treat epilepsy prompts us to make clear our commitment to patients and their families in the advent of a potentially new and effective treatment for severe, sometimes life threatening, seizures. Our current view, based on available evidence obtained from clinical trials, is that certain cannabinoids show promise in the treatment of severe epilepsy, particularly in children with Dravet syndrome, but that other cannabinoids are inadequately tested or known to be potentially harmful. As a group, we are committed to the care of all patients with epilepsy but it is our solemn duty to ensure that all treatments are proven to be both beneficial and safe. This is particularly important when a new drug is used in a child's developing brain. Despite this pressure has emerged from certain quarters to abandon the tried and tested regulatory pathway in favour of untested and potentially harmful treatments; not only this but such pressure has sought to undermine one of the core values of medical treatment that of the doctor-patient relationship. This is what has prompted this statement.

To date the limited scientific evidence on cannabis derivatives in epilepsy is based on the use of a compound called Cannabidiol (CBD). This has been developed and tested by a pharmaceutical company called GW Pharma and is known as 'Epidiolex'. Epidiolex has orphan drug status and fast track designation with the FDA in the USA for the treatment of epilepsy in Dravet syndrome. There is emerging evidence for its use in other forms of severe epilepsy. It is expected that Epidiolex will be available for compassionate use through a government sponsored access programme for those with severe epilepsy who have failed other treatments in 2017 (See HPRA report) and guidelines are being drawn up for this programme. No other cannabis derivatives or products have been adequately studied to a level that they are proven to be effective and safe to use in clinical practice. Specifically, products containing THC (a cannabis derivative with potentially harmful psychoactive effects) remain inadequately tested. Though the NCPE is committed to progressing the use of new treatments for epilepsy, currently the main barrier to the prescribing of cannabis derivatives for epilepsy is the lack of clinical evidence of its long-term efficacy, as well as lack of data on long-term side effects.

Apart from 'Epidiolex' no other cannabis product has been endorsed by any scientific or licensing authority. Professional associations such as the American Academy of Neurology(AAN) and the American Epilepsy Society (AES) have called for higher quality research before endorsing the use of other cannabis derivatives. The NECP cannot endorse the prescription any other cannabis products for epilepsy at this time. We keep abreast of all scientific data and if future evidence demonstrates that other cannabis products are safe and effective and once they pass all stages of the national regulatory pathway in the HPRA, they will then be offered to suitable patients.

Colin P Doherty MD FRCPI

Clinical Lead for the National Clinical Programme for Epilepsy

On behalf of The Clinical Advisory Group for the NCPE