Last reviewed: September 2018
Last updated: September  2018

Cannabidiol approved by the US Food and Drug Administration (FDA) to treat rare, severe forms of epilepsy in children

Cannabidiol oral solution has been approved by the FDA in the US for the treatment of seizures associated with Lennox-Gastaut syndrome and Dravet syndrome, in patients 2 years of age and older.

This is the first FDA-approved drug that contains a purified drug substance derived from marijuana. It is also the first FDA-approved drug for the treatment of patients with Dravet syndrome.

Its effectiveness has been studied in 3 randomised, double-blind, placebo-controlled trials involving 516 patients with either Lennox-Gastaut syndrome or Dravet syndrome. Cannabidiol oral solution, taken along with other medications, was shown to be effective in reducing the frequency of seizures when compared with placebo. The most common side effects in patients randomised to cannabidiol were: sleepiness, sedation, and lethargy; elevated liver enzymes; decreased appetite; diarrhoea; rash; fatigue, malaise, and weakness; insomnia, sleep disorder, and poor quality sleep; and infections.

See Management: emerging treatments

Original source of update

European Medicines Agency (EMA) strengthens measures to avoid use of valproate medicines in pregnancy

In 2018 the EMA announced stronger measures aimed at avoiding the exposure of babies to valproate medicines in the womb. Under the new restrictions, valproate medicines are contraindicated in epilepsy during pregnancy due to the high risk of congenital malformations and developmental problems in the child. However, the EMA recognises that for some women with epilepsy it may not be possible to stop valproate and they may have to continue treatment during pregnancy with appropriate specialist care.

In addition, valproate medicines must not be used in female patients of childbearing potential unless there is a pregnancy prevention programme in place that includes:

  • an assessment of the patient’s potential for becoming pregnant

  • pregnancy tests before starting and during treatment as needed

  • counselling about the risks of valproate treatment and the need for effective contraception throughout treatment

  • a review of ongoing treatment by a specialist at least annually

  • a risk acknowledgement form that patients and prescribers will go through at each such annual review to confirm that appropriate advice has been given and understood.

The EMA said the new measures were put in place because of evidence suggesting that information on the risks of valproate use in pregnancy was still not getting through to women despite earlier steps aimed at ensuring this.

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Original source of update



History and exam

Key diagnostic factors

  • presence of risk factors
  • staring spells or inattention
  • tonic-clonic seizures
  • brief, arrhythmic muscular jerking movements
  • eyes rolling back in head
  • intercurrent illness
  • unexplained falls

Other diagnostic factors

  • incontinence
  • tongue biting
  • post-ictal phenomena
  • precipitated by fatigue or lack of sleep
  • precipitated by light or noise
  • developmental delay
  • neurocutaneous stigmata

Risk factors

  • genetic predisposition or FHx
  • perinatal asphyxia
  • metabolic/neurodegenerative disorders
  • head trauma
  • structural abnormalities of the central nervous system (CNS)
  • autistic spectrum disorder
  • central nervous system (CNS) infection
  • neurocutaneous syndromes
  • Hx of febrile seizures

Diagnostic investigations

1st investigations to order

  • electroencephalogram (EEG)
  • blood glucose level
  • basic metabolic panel
  • full blood count (FBC)
  • ECG
Full details

Investigations to consider

  • magnetic resonance imaging (MRI) brain
  • computed tomography (CT) brain
Full details

Treatment algorithm


Authors VIEW ALL

Consultant Paediatric Neurologist

St. Mary's Hospital

Imperial College Healthcare NHS Trust




LM has attended educational events hosted by Eisai (Perampanel/fycompa) and by Novartis (Everolimus for Tuberous Sclerosis patients).

Pediatric Neurologist

Pediatric Hospital No 1




AN declares that she has no competing interests.

Dr Leena Mewasingh and Dr Alla Nechay would like to gratefully acknowledge Dr Ewa Posner, a previous contributor to this monograph. EP declares that she has no competing interests.

Peer reviewers VIEW ALL

Assistant Professor of Neurology and Pediatrics

Johns Hopkins Hospital




AH has received research support from the National Institutes of Health that is greater than 6 figures. ALH's research is funded in part by the National Institutes of Health. He is the co-author of one review that is referenced in this monograph.

Pediatric Neurologist

Kinderneurologisches Zentrum Mainz




RW declares that he has no competing interests.


Paediatric Neurology Emeritus

Fraser of Allander Neurosciences Unit

Royal Hospital for Sick Children

Honorary Professor in Paediatric Neurology and Senior Research Fellow

Department of Child Health

Division of Developmental Medicine

University of Glasgow




JS declares that he has no competing interests.

Honorary Clinical Lecturer

Paediatric Neurology

Newcastle General Hospital




AB has previously worked as part of a clinical team with EP. AB declares that she has no competing interests.

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