Parkinson disease: Some early research suggests that taking high doses of CBD might make muscle movement and tremors worse in some people with Parkinson disease.
When applied to the skin: There isn’t enough reliable information to know if CBD is safe or what the side effects might be.
Over 80 chemicals, known as cannabinoids, have been found in the Cannabis sativa plant. Delta-9-tetrahydrocannabinol (THC) is the most famous ingredient in cannabis. But CBD is obtained from hemp, a form of the Cannabis sativa plant that only contains small amounts of THC. CBD seems to have effects on some chemicals in the brain, but these are different than the effects of THC.
For information on using prescription CBD, a product called Epidiolex, speak with a healthcare provider.
Children: It is possibly safe for children to take a specific prescription CBD product (Epidiolex) by mouth in doses up to 25 mg/kg daily. This product is approved for use in children with certain conditions who are at least 1 year old. It isn’t clear if other CBD products are safe in children.
CBD has most often been used by adults in doses of 200 mg or less per day. Speak with a healthcare provider to find out what dose might be best for a specific condition.
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.
How effective is it?
When taken by mouth: CBD is possibly safe to take in appropriate doses. Doses of up to 200 mg daily have been used safely for up to 13 weeks. With the guidance of a healthcare provider, a specific prescription CBD product (Epidiolex) has been used at higher doses and for longer durations.
Laws passed in 2018 made it legal to sell hemp and hemp products in the US. But that doesn’t mean that all CBD products made from hemp are legal. Since CBD is an approved prescription drug, it can’t be legally included in foods or dietary supplements. CBD can only be included in “cosmetic” products. But there are still CBD products on the market that are labeled as dietary supplements. The amount of CBD contained in these products is not always the same as what is stated on the label.
Oral tablets and capsules have an onset of between 1 and 6 hours, and a longer duration of 6 to 8 hours. Fixen said these products may be a better option for patients seeking relief over a long period of time, and patients should be advised that if taken with a high fat or high calorie meal, oral options increase peak concentration.
Patients should be aware of adverse effects, which can include nausea, diarrhea, headache, drowsiness or sedation, fatigue, and dry mouth. It may increase the effects of alcohol, anti-epileptic medications, antipsychotics, benzodiazepines, beta-blockers, opioids, selective serotonin reuptake inhibitors, and warfarin.
With a wide array of cannabidiol (CBD) and CBD extract products available without a prescription, pharmacists have an increasingly important role to play in counseling patients on which products may work for them and how they should be properly used.
By carefully considering pharmacokinetics, potential adverse effects, and appropriate products for their patients, Fixen said pharmacists can effectively counsel their patients on safe products and appropriate usage.
When selecting CBD products to carry in the pharmacy or recommend to patients, Fixen said clinicians should demonstrate a framework and consider various delivery methods. Common CBD delivery methods include inhaled products, suppositories, oral products, and topical creams or patches.
Products should not be considered if they are made from a foreign source; isolate, distillate, or say “pure CBD;” only list total cannabinoid content; and are derived from the seed or stalk of a hemp plant.
Finally, Fixen outlined some basic standards to maintain when considering CBD products. Pharmacists should recommend products that are made in a state that has legalized recreational and medical use of cannabis, that are full or broad-spectrum CBD oil extract, that have a certificate of analysis and labeling indicating the amount of CBD per serving, and CBD that is obtained from high-resin cannabis.
The endocannabinoid system (ECS) is a complex cell-signaling system which regulates and balances many processes. It is composed of endocannabinoids, including anandamide (AEA) and 2-arachidonoylglycerol (2-AG). Pharmacists should consider the ECS for many reasons when discussing CBD products with patients, but most notably because it modulates dopamine, serotonin, glutamate, norepinephrine, gamma-aminobutyric, and acetylcholine.
CBD is currently FDA-approved for the treatment of Dravet and Lennox-Gastaut syndrome, two childhood seizure disorders. 4 Randomised controlled trials (RCTs) have shown that, when CBD is added to existing anti-epileptic medication in patients with these syndromes, seizure frequency decreases. 5 , 6
How this fits in
Moreover, preclinical studies have demonstrated anxiolytic effects of CBD. 3 , 8 – 10 Crippa et al found that in patients with generalised anxiety disorder given 400 mg of oral CBD, there was decreased cerebral blood flow to anxiety processing areas of the brain and a decrease in patient-reported anxiety when compared to placebo. 8 CBD in one double-blinded placebo-controlled RCT decreased symptoms of social anxiety disorder patients and fear of public speaking. 10 CBD may also reduce psychotic symptoms of schizophrenia. 11
CBD’s ineffectiveness in improving self-reported health in patients in the cancer and neurological groups may be due to the high heterogeneity of the clinical presentations within these groups. Additionally, patients within these groups had more severe disease progression compared to the mental health and non-cancer pain symptom groups, which may have limited efficacy.