The US Food and Drug Administration has approved Epidiolex, a cannabidiol (CBD) oral solution, to treat seizures linked to tuberous sclerosis complex (TSC), a rare genetic disease that causes benign tumors to grow on the brain and other organs such as the eyes, heart, and lungs.
Occurring in around 1 in 6,000 people, TSC typically affects the central nervous system. Aside from seizures, it is also known to cause developmental delay and behavioral problems.
Previously, Epidolex had been approved to treat seizures from two rare forms of epilepsy: Lennox-Gestaut syndrome (LGS) and Dravet syndrome (DS). It is also currently the only FDA-approved drug to contain a purified substance derived from cannabis.
Prior to approval, Epidolex underwent a randomized, double-blind, placebo-controlled trial where 148 patients out of 224 received the drug. The purpose of the study was to measure the difference from baseline in seizure frequency.
In the end, the researchers found that patients treated with Epidolex had a significant reduction in the frequency of seizures during the treatment periods than those on the placebo. The effects were seen within eight weeks and remained throughout the 16-week treatment period.
The most common side effects form the drug in patients with TSC included diarrhea, elevated liver enzymes, decreased appetite, fever, sleepiness, and vomiting. Less common side effects for patients, regardless of condition, include liver injury, reduced weight, anemia, and increased creatinine, a sign of impaired kidney function.
Given its potential for negative side effects (findings from a human trial showing that between 5% and 20% of patients receiving the drug suffered from liver damage), extreme care is needed for those who take it. As such, after prescription by a physician, parents, caregivers, and families are advised to monitor any unusual changes in mood or behavior, including worsening depression and suicidal thoughts, among those taking the drug.