Cannabidiol (Epidiolex) oral solution is the first purified drug derived from marijuana to be approved by the Food and Drug Administration. It is approved for the treatment of two rare and severe types of seizure disorder, Lennox-Gastaut syndrome and Dravet syndrome. It is also the first drug specifically approved to treat Dravet syndrome. The drug is only approved for use in patients two years of age and older.

Cannabidiol is a chemical component of marijuana, but it does not produce intoxication or euphoria. The psychoactive effects of marijuana are produced by another chemical, tetrahydrocannabinol. Cannabidiol also does not produce physical dependence. Because the drug is made from a component of the cannabis plant, it is a Schedule I controlled substance.

Although the medical use of marijuana has been promoted for some time (some states have legalized medical marijuana use), many providers have been hesitant to prescribe it because of concerns about quality control and appropriate dosing. The approval of cannabidiol now offers uniform strength and delivery of this component of marijuana, which may alleviate such concerns.

Both Lennox-Gastaut and Dravet syndromes produce frequent and difficult-to-control seizures in children. Lennox-Gastaut syndrome typically begins between ages three and five years and several types of seizures can occur. Three-quarters of those with Lennox-Gastaut experience tonic seizures, seizures lasting from seconds to a minute in which a person's muscles stiffen and the person may lose consciousness. Dravet syndrome, a rare genetic condition, appears during the first year of life. It initially presents with frequent febrile seizures, and other seizure types will occur. There is also an elevated risk of status epilepticus. The frequency and severity of the seizures from these syndromes greatly impair quality of life.

Cannabidiol was studied in three randomized, double-blind, placebo-controlled clinical trials, two involving patients with Lennox-Gastaut syndrome and one involving patients with Dravet syndrome. In all three trials, when combined with other therapy, cannabidiol was more effective than placebo in reducing the number of seizures.

The most common adverse effects (appearing in 10% or more of patients) were somnolence; elevated liver enzyme levels; decreased appetite; diarrhea; rash; fatigue, malaise, and weakness; insomnia; sleep disorder; poor-quality sleep; and infections. Somnolence is likely to diminish with continued treatment. The rise in liver enzyme levels is usually minimal. The risk of increases in liver enzyme levels is greater if the patient takes larger doses of cannabidiol or is also taking the antiseizure drug valproate. Like all antiepileptic drugs, cannabidiol carries a warning that it might induce suicidal ideation, depression, aggression, or panic attacks.

Nurses should ensure that blood work is done at baseline before the patient begins cannabidiol therapy to assess liver function (alanine aminotransferase, aspartate aminotransferase, and total bilirubin levels). Blood work should be repeated after one month, three months, and six months of treatment; if the enzyme levels are greater than three times the upper limit of normal, the patient is at risk for liver damage. Assess these patients carefully for signs and symptoms of liver disease, such as nausea, vomiting, right upper quadrant abdominal pain, fatigue, anorexia, jaundice, and dark urine. Instruct parents and patients to measure doses with the calibrated measuring device included in the packaging, rather than a household teaspoon or tablespoon. Nurses should follow the administration instructions included in the labeling (available online at http://www.accessdata.fda.gov/drugsatfda_docs/label/2018/210365lbl.pdf) to teach patients how to prepare the medication bottle and use the dosing syringe. Nurses should let patients know that information will also accompany each filled prescription.