Side effects
Side effects

CBD has extremely low toxicity and no adverse effects with short-term use. On rare occasions, mild to moderate adverse effects have been shown, with long-term use[1]. The most common (but still very rare) dose-related side effects are sleepiness and sedation[2][3][4]. These are observed in early treatment and are likely to diminish over time. These adverse effects can impair the ability to operate machinery or drive. 

Extreme caution is required when CBD is co-administered with benzodiazepines, opioids, and other CNS depressants. Such combinations may result in severe respiratory depression[5][6]. 

Although rare, users experiencing discomfort even after a relatively low dose intake of CBD may be allergic to cannabidiol itself or another ingredient in the formulation taken, for example (sesame oil)[7]. If this is the case, they should immediately stop its administration and seek medical assistance, if necessary.

Possible drug-drug interactions
Every potential CBD patient should not consume it without prior consultation with their medical doctor, especially when CBD is to be added to an existing therapeutic regimen that contains drugs mainly metabolized by the liver. Such drug-drug interactions are more likely between CBD and the two anti-epileptic drugs - Valproate and Clobazam. Still, there are also potential interactions between CBD and CYP1A2 substrates (theophylline, caffeine), CYP2B6 substrates (bupropion, efavirenz), UGT1A9 (diflunisal, propofol, fenofibrate), UGT2B7 (gemfibrozil, lamotrigine, morphine, lorazepam), and CYP2C8 and CYP2C9 (phenytoin) and others[8].
Pregnancy and breastfeeding

There is scarce information regarding CBD and its use during pregnancy or breastfeeding. For that reason, women are advised to abstain from products CBD when pregnant or breastfeeding.

Renal and hepatic impairment

For patients with renal / hepatic impairment it is highly recommended to consult with their doctor, prior to CBD intake.


1. Larsen C and Shahinas J: Dosage, Efficacy and Safety of Cannabidiol Administration in Adults: A Systematic Review of Human Trials. J Clin Med Res 12: 129-141, 2020. 

2. Devinsky O, Marsh E, Friedman D, et al: Cannabidiol in patients with treatment-resistant epilepsy: an open-label interventional trial. The Lancet Neurology 15: 270-278, 2016. 

3. Neale M: Efficacy and safety of cannabis for treating children with refractory epilepsy. Nursing children and young people 29: 32-37, 2017. 

4. Thiele EA, Marsh ED, French JA, et al: Cannabidiol in patients with seizures associated with Lennox-Gastaut syndrome (GWPCARE4): a randomized, double-blind, placebo-controlled phase 3 trial. Lancet (London, England) 391: 1085-1096, 2018. 

5. Ali S, Scheffer IE and Sadleir LG: Efficacy of cannabinoids in paediatric epilepsy. Developmental medicine and child neurology 61: 13-18, 2019. 

6. Gaston TE and Szaflarski JP: Cannabis for the Treatment of Epilepsy: an Update. Current neurology and neuroscience reports 18: 73, 2018. 

7. Huestis MA, Solimini R, Pichini S, Pacifici R, Carlier J and Busardò FP: Cannabidiol Adverse Effects and Toxicity. Curr Neuropharmacol 17: 974-989, 2019