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
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.See Management: approach See Management: treatment algorithm
Seizures may occur as a stand-alone event or may recur (epilepsy).
Aetiology can be structural, genetic, infectious, metabolic, immune, or unknown.
An attempt should be made to identify the type(s) of epilepsy and the epilepsy syndrome by recognising a pattern of seizure types, clinical features, and EEG characteristics.
Detailed history is of paramount importance in the diagnosis, as key diagnostic factors lie in the history as opposed to ancillary investigations.
Main treatment options will depend on the epilepsy syndrome and include anticonvulsants, a ketogenic diet, vagus nerve stimulation, and surgery as well as consideration of lifestyle factors.
With the revised and updated classification by the International League Against Epilepsy (ILAE) Commission on Classification and Terminology, generalised seizures are now understood to originate at some point within the brain and rapidly engage bilaterally distributed networks. This can include both cortical and subcortical structures and may not necessarily involve the entire cortex.   The new ILAE classification presents three levels to help guide the clinician: 1) diagnosis of the seizure type; 2) diagnosis of the epilepsy type (focal epilepsy, generalised epilepsy, combined focal and generalised epilepsy, and an unknown group); 3) these two levels help determine the epilepsy syndrome, which is often an electroclinical syndromic diagnosis. Aetiology is taken into account along each step. 
Seizures may occur as a stand-alone event or they may recur, in which case the term 'epilepsy' is used. This topic addresses generalised epilepsies. Previous terminology of 'secondarily generalised' seizure (i.e., a focal-onset seizure that spread to involve the rest of the body) has now changed to 'focal to bilateral tonic-clonic seizure'. It is also recognised that if the onset of a seizure is unwitnessed or cannot be described, this would be an 'unknown onset tonic-clonic seizure'. 
Febrile seizures are dealt with separately. This topic does not include seizures in neonates.
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 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.
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.
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
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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