The results of recent clinical trials indicate that Cannabidiol (CBD) reduces seizures among patients with refractory epilepsies of various etiologies. Most of these clinical studies report efficacy over short time periods (<1 year). Is CBD effective long term?
Yes. A May 2021 study demonstrated that CBD does not lose its efficacy in controlling seizures over a treatment period of up to 60 months. In addition, other results on the efficacy and tolerability of CBD in the treatment of refractory epilepsies, suggest that CBD is an effective, safe, and well-tolerated anti-epileptic drug for long-term use.
The long-term efficacy of cannabidiol in the treatment of refractory epilepsy. Sandip Patel, Reid Grinspoon, Bradley Fleming, Lauren A. Skirvin, Christina Wade. 29 May 2021 https://doi.org/10.1111/epi.16936
For what health conditions is the therapeutic applicability of CBD being evaluated?
The range of conditions for which CBD has been (or is being) assessed is quite diverse. Currently, clinical trials are evaluating CBD’s analgesic, neuroprotective, antiepileptic, anxiolytic, antipsychotic, anti-inflammatory, antitumor and anti-hypoxia/ischemia properties. According to a March 2021 search of the National Library of Medicine’s database, clinicaltrials.gov, there were more than 300 registered clinical trials that involve the use of CBD as a therapeutic intervention.
The FDA has issued a document with full prescribing information for a CBD product, Epidiolex. According to this document, are there any blood tests that should be performed prior to initiating treatment with Epidiolex?
Yes, it is suggested that serum transaminases (ALT and AST) and total bilirubin levels be obtained prior to starting treatment with Epidiolex. It has been found that some patients taking Epidiolex experience an increase in serum levels of the hepatic transaminases.
Highlights for prescribing information for Epidiolex https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/210365lbl.pdf
Does pretreatment with CBD prevent the transient psychotic symptoms induced by THC?
According to a study in humans, pretreatment with CBD does diminish THC’s psychotic effects. This particular study involved 6 healthy volunteers who were given THC intravenously on two separate occasions – once with a placebo pretreatment and once with a CBD pretreatment.
Atakan Z. Cannabis, a complex plant: different compounds and different effects on individuals. Ther Adv Psychopharmacol 2012 Dec; 2(6):241-254. doi:10.1177/2045125312457586. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3736954/
Has any national drug administration approved a CBD-containing product for therapeutic use in conditions other than epilepsy?
Yes. The oromucosal spray Sativex (nabiximols) is a cannabis extract that contains the principal cannabinoids delta-9-tetrahydrocannibinol (THC) and cannabidiol (CBD) in a 50:50 ratio, as well as specific minor cannabinoids and other non-cannabinoid components. Regulatory approval has been obtained in numerous countries outside the United States for the treatment of multiple sclerosis symptoms (nerve pain, spasticity, overactive bladder, and other symptoms).
Epidiolex is an FDA-approved oral CBD solution indicated for the treatment of seizures associated with Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), or tuberous sclerosis complex (TSC) in one year of age and older. Can it be prescribed for indications other than these three seizure disorders (i.e. off label)?
Yes, Epidiolex may be prescribed off-label, but insurance coverage may be subject to pre-authorization.
GW Pharmaceuticals press release: “GW Pharmaceuticals plc and Its U.S. Subsidiary Greenwich Biosciences, Inc. Announce That EPIDIOLEX® (cannabidiol) Oral Solution Has Been Descheduled And Is No Longer A Controlled Substance” April 6, 2020. https://ir.gwpharm.com/news-releases/news-release-details/gw-pharmaceuticals-plc-and-its-us-subsidiary-greenwich-1 Accessed April 30, 2020. GW Pharmaceuticals website. Sativex. https://www.gwpharm.com/healthcare-professionals/sativex
St. John’s wort is an over the counter medication used as a remedy for mild depression. Does St. John’s wort interact with CBD?
Yes. St. Johns wort inhibits some of the liver enzymes that metabolize CBD. As a result, there is an increase in bioavailability of CBD, and a possible increase of adverse effects associated with CBD consumption.
Brown JD, Winterstein AG. Potential Adverse Drug Events and Drug-Drug Interactions with Medical and Consumer Cannabidiol (CBD) Use. J Clin Med. 2019;8(7):989. Published 2019 Jul 8. doi:10.3390/jcm8070989. https://pubmed.ncbi.nlm.nih.gov/31288397/
A seizure disorder is a qualifying condition in many medical marijuana state programs. Does CBD interact with commonly prescribed anti-epileptic medications?
Yes. According to a presentation at the 2014 annual meeting of the American Epilepsy Society, an increasing dose of CBD was associated with significant increases in serum levels of topiramate, rufinamide, and N-desmethylclobazam. Also, there is a significant association between increasing CBD doses and increased zonisamide and eslicarbazepine serum levels.
Friedman D, Cilio MR, Tilton N, et al. The effect of epidiolex (cannabidiol) on serum levels of concomitant anti-epileptic drugs in children and young adults with treatment-resistant epilepsy in an expanded access program. Presented at the annual meeting of the American Epilepsy Society, Seattle, December 5–9, 2014; abstract.