Research On Cannabidiol for Patients with Treatment-Resistant Epilepsy

Out of the 500 species of plants discovered and documented, Cannabis sativa L is one.

This plant is well known because of the famous recreational drug derived from it – marijuana. Marijuana is also called cannabis.

It is a psychedelic drug, used by some and abused by many. The name of the compound pre-dominant in marijuana is THC (tetrahydrocannabinol)

Another budding extract being used in research is cannabidiol (CBD). Unlike marijuana, it is non-psychedelic as it doesn’t cause any hallucinations.

What is Epilepsy?

Epilepsy is a neurological disorder where the activity of the brain becomes erratic, causing seizures, unusual behaviour and loss of awareness.

It is a disorder that affects the central nervous system.

Seizures may cause someone to sit extremely still while staring into space, or it can make them twitch their hands and legs. People who stare into space blankly during a seizure are people who are said to suffer from an “absence seizure”.

A single seizure is not enough for an epilepsy diagnosis. At least two or more seizures are needed for epilepsy to be considered as a possibility.

Childhood epilepsy is sometimes outgrown with age.

Seizures are of two types.

  • Focal seizures – When seizures result from abnormal activity in one area of the brain. Can be with or without loss of awareness
  • Generalized seizures – When seizures result from abnormal activity in all the areas of the brain.

What happened in the study

About one-third of people suffering from epilepsy are resistant to drugs.

This has a severe mortality rate. Epilepsy treatments with cannabis extracts have garnered much interest, but the scientific data to present it is very less.

The aim of the study was to establish if an addition of cannabidiol to existing anti-epileptic regimens would be safe, if it would be tolerated, and if it was effective in treating children and young adults with treatment-resistant epilepsy.

The type of study conducted was an open-label study.

Open-label is the opposite of double-blind placebo controlled trial, which means both the health providers and the patients are aware of the drug or treatment being given.

The lower and upper limit of the age of the patients participating in this trial was 1-30 years.

Everyone suffered from severe, intractable, childhood-onset, treatment-resistant epilepsy.

This means their epilepsy was extremely difficult to control or manage, and that the adults suffering from epilepsy have been suffering from epilepsy since childhood.

These patients have been receiving steady doses of the anti-epileptic medicine prescribed to them at the beginning of the trial.

This study was multicenter, meaning it was conducted at multiple health centres. This particular study was conducted across 11 epilepsy care centres across the USA.

Patients were given cannabidiol orally at 2-5 mg/kg per day. This dosage was increased until the patient’s body was intolerant to it, or the upper limit was maintained at around 25 mg/kg or 50 mg/kg per day.

The main aim was to establish the safety and the tolerability of CBD in patients. It was also noticed that the primary efficacy endpoint was median percentage change in the mean monthly frequency of motor seizures at 12 weeks.

This means, the statistical value that marked the maximum efficacy of CBD, was the percentage change in the mean of the occurrence of motor seizures at 12 weeks.

Comparisons of the percentage change in frequency of occurrence of motor seizures were done with a Mann-Whitney U test. Mann Whitney U test, also called Wilcoxon Rank sum test, is another method of finding a value of statistical significance that can be used to draw inferences in clinical trials.

214 patients were enrolled between Jan 15, 2014, and Jan 15, 2015, in this study. 76% of the patients, (ie 162 of them) who had 12 weeks of follow up after the first dose of CBD were included in the safety and tolerability analysis. 64% (ie 137 patients) were included in the analysis of the efficiency of CBD.

20% of the patients in the analysis of the safety of CBD (33 patients) suffered from Dravet Syndrome. 19% of the patients (ie 31) had Lennox Gastaut Syndrome.

Dravet Syndrome is a rare disorder that causes the affected person to have a severe form of epilepsy. Lennox Gastaut syndrome causes the affected person to have multiple seizures and have an intellectual disability.

The remaining patients had different types of intractable epilepsies with different causative features.

128 patients of the 162 patients (79%) in the safety group reported adverse effects. More than 10% of the patients showed effects like somnolence (41 patients, ie 25%]), decreased appetite (31 patients, ie 19%), diarrhoea (31 patients, ie 19%), fatigue (21 patients, ie 13%), and convulsion (18 patients, ie 11%).

Somnolence means fatigue causing. Convulsions mean sudden involuntary movements in the muscles of the body.

5 patients discontinued the treatment due to an adverse event. 48 patients reported serious adverse events. There was one death, which was not related to this trial.

20 patients had severe side effects which were due to CBD dosage. 9 patients suffered from status epilepticus.

Status epilepticus is defined as the condition where a single seizure lasts as long as 30 minutes, or there are two or more seizures back to back without the person regaining consciousness in between.

The median value of the frequency of monthly seizures was 30, maintaining an IQR of 11·0-96·0. IQR is the method used in determining statistically relevant values when there are extreme values. The median value was 15·8 (IQR – 5·6-57·6) over the 12 week treatment period.

There was a median reduction in the monthly seizures by 36.5%.

What did the study conclude?

CBD dosage helped in reduction of occurrence of seizures by 36.5%. Five patients left the trial due to the serious side effects.

This trial with CBD brought some relief to epileptic patients. CBD was adequately safe to use on children and young adults.

What does this mean?

CBD may reduce the frequency of occurrence of seizures in patients suffering from treatment-resistant epilepsy. If researched well, this may pave the way for a scientific breakthrough for prophylaxis for epilepsy and other epilepsy-related disorders.

Read the research paper here-
https://www.ncbi.nlm.nih.gov/pubmed/26724101

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