Is CBD Oil Safe? Possible Side Effects and InteractionsMar 10, 2022
Written by: Henry Emmons, MD and Tim Culbert, MD
Low to moderate doses of CBD are considered quite safe and well-tolerated. However, side effects and drug interactions can occur.
CBD Side Effects
As noted, CBD is generally considered well-tolerated. However, CBD can cause side effects. These side effects can be more confusing given the unreliability of the purity and dosage of CBD in products (which is why purchasing a high-quality product is essential).
Side effects of CBD may inlude:
- Dizziness and lightheadedness
- Dry Mouth
- Increased Appetite
- Lowered blood pressure
In my practice, I find that the most common side effect is very mild sedation, though that is usually not a problem for those with high anxiety, and may be a welcome effect for those with sleep trouble. Like most things that are calming, adding CBD to other sedating medications, or combining CBD with alcohol, may cause excess sedation.
There is too little information about the safety of CBD during pregnancy or while breastfeeding, so it is not recommended.
Research suggests many side effects that occur with CBD use are likely the result of drug-to-drug interactions between CBD and other medications an individual may be taking. That's why it's so important to speak with your doctor before starting any supplement, and this is particularly true with CBD.
Here's how these interactions occur: CBD is broken down by the body via the same pathway as many prescription drugs. If multiple compounds are competing in this pathway (e.g., CBD and a prescription drug), then something called "altered concentration" can occur. This means that too little or too much of the drug is left in the body. When too little remains, a drug may no longer work as intended. When too much remains, side effects may increase.
This altered concentration should be considered when taking CBD with any other prescription, supplement, or over-the-counter product that causes sleepiness. These include (but are not limited to):
- Herbal products to support sleep
Additionally, there are other medication interactions with CBD that can be serious. Penn State College of Medicine has a really handy list of medications that may be impacted by altered concentration due to a combination with cannabinoids. Unfortunately, this list does not make any distinctions between CBD or THC, but it provides some guidance. Bring this list to your doctor before starting any CBD product.
Penn State also found potentially serious interactions between prescription CBD and THC products and the following products:
- Warfarin and other blood thinners
- Amiodarone (heart medication)
- Levothyroxine (thyroid medication)
- Seizure medications (clobazam, lamotrigine, valproate)
*Note: Some of the supplements discussed in this article can cause side effects, but many people tolerate them much better than prescription medications. They are generally considered safe, however, they should not be started without your doctor’s knowledge and supervision. If you are taking medication already, be sure to talk with your doctor before adding any of these items. If you are considering going off medication, remember never to stop your medication suddenly—always consult with your doctor about how to safely taper off any psychiatric medication. See terms.
**These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
- Abrams, D. (2018). The therapeutic effects of Cannabis and cannabinoids: An update from the National Academies of Sciences, Engineering and Medicine report. European journal of internal medicine, 49, 7-11.
- Atakan, Z. (2012). Cannabis, a complex plant: different compounds and different effects on individuals. Therapeutic advances in psychopharmacology, 2(6), 241-54. doi:10.1177/2045125312457586
- Atalay, S., Jarocka-Karpowicz, I., & Skrzydlewska, E. (2019). Antioxidative and Anti-Inflammatory Properties of Cannabidiol. Antioxidants, 9(1), 21. https://doi.org/10.3390/antiox9010021
- Ballard, C. R., & Junior, M. R. M. (2019). Health benefits of flavonoids. In Bioactive compounds (pp. 185-201). Woodhead Publishing.
- Bridgeman, M. B., & Daniel T. A. (2017). Medicinal cannabis: History, pharmacology, And implications for the acute care setting. P&T: A peer-reviewed journal for formulary management, 42(3), 180-188.
- Cox-Georgian, D., Ramadoss, N., Dona, C., & Basu, C. (2019). Therapeutic and medicinal uses of terpenes. In Medicinal Plants (pp. 333-359). Springer, Cham.
- García-Gutiérrez, M.S., Navarrete, F., Gasparyan, A., Austrich-Olivares, A., Sala, F., & Manzanares, J. (2020). Cannabidiol: A Potential New Alternative for the Treatment of Anxiety, Depression, and Psychotic Disorders. Biomolecules, 10(11). https://doi.org/10.3390/biom10111575
- Kocis, P, T., & Vrana, K, E. (2020). Delta-9-Tetrahydrocannabinol and Cannabidiol Drug-Drug Interactions. Med Cannabis Cannabinoids, 3:61-73. doi: 10.1159/000507998
- Lee, C. H., & Giuliani, F. (2019). The Role of Inflammation in Depression and Fatigue. Frontiers in immunology, 10, 1696. https://doi.org/10.3389/fimmu.2019.01696
- Leonard, B. E. (2014). Impact of inflammation on neurotransmitter changes in major depression: An insight into the action of antidepressants, Progress in Neuro-Psychopharmacology and Biological Psychiatry, 48. 261-267. https://doi.org/10.1016/j.pnpbp.2013.10.018.
- Morales, P. et al. (2017). Molecular targets of the phytocannabinoids: A complex picture. Progress in the chemistry of organic natural products, 103, 103-131. doi:10.1007/978-3-319-45541-9_4
- Noreen N., Muhammad, F., Akhtar, B., Azam, F., & Anwar, M. I. (2018). Is cannabidiol a promising substance for new drug development? A review of its potential therapeutic applications. Crit Rev Eukaryot Gene Expr, 28(1), 73-86. doi: 10.1615/CritRevEukaryotGeneExpr.2018021528.
- Sales, A. J., Crestani, C. C., Guimarães, F. S., Joca, S. (2018). Antidepressant-like effect induced by Cannabidiol is dependent on brain serotonin levels. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 86. 255-261. https://doi.org/10.1016/j.pnpbp.2018.06.002.
- Sales, A. J., Fogaça, M. V., Sartim, A. G., et al. (2019). Cannabidiol induces rapid and sustained antidepressant-like effects through increased BDNH signaling and synaptogenesis in the prefrontal cortex. Mol Neurobiol, 56, 1070–1081. doi:10.1007/s12035-018-1143-4.
- Sarris, J. et al. (2020). Medicinal cannabis for psychiatric disorders: A clinically-focused systematic review. BMC Psychiatry, 20(1). doi:10.1186/s12888-019-2409-8
- Wong, S. S., & Wilens, T. E. (2017). Medical cannabinoids in children and adolescents: a systematic review. Pediatrics, 140(5).