Derived from the hemp plant, Cannabidiol (CBD) has become a popular treatment for back pain and other conditions. CBD has few side effects and is generally considered low risk. However, if you take prescription or over-the-counter medications you should be aware of potential interactions, particularly if the CBD is taken orally. Topical CBD products do not go through the bloodstream so there is less chance of them interacting with medications.
CBD, grapefruit, and drug metabolism
Like grapefruit and grapefruit juice, CBD can affect how some medications are metabolized. If your doctor or pharmacist has said to avoid grapefruit or grapefruit juice with your medication, this may be a good time to ask if oral CBD oil may also interact with your medication.
Many medications, such as those used to treat high blood pressure or fight off infection, come with a warning to avoid grapefruit juice and similar products. This is because grapefruit inhibits the activity of a group of liver enzymes (where many drugs are metabolized or broken down by the body) called cytochrome P450. Cannabidiol also inhibits the activity of cytochrome P450,1 which means that it can alter the way the body metabolizes different drugs—either causing there to be too much or too little in the system.
More research is needed to determine if there is a specific dose at which CBD begins to inhibit cytochrome 450. You should speak with a health care provider to establish the amount of CBD, if any, that is safe to take.
CBD and anti-seizure medication
According to one study, people who take anti-epileptic medication for refractory epilepsy, such as clobazam (Onfi, Sympazan), may benefit from taking CBD.2 This is because both drugs are metabolized in cytochrome P450 and may enhance the medication's effects. Dose adjustments of clobazam may be necessary and this combination should be strictly monitored by a health care professional.
CBD and blood thinners
Drugs used to thin blood, such as warfarin (Coumadin), and drugs that carry an increased risk of bleeding, such as ibuprofen (Advil) or naproxen (Aleve), have been shown to interact with CBD.
CBD likely blocks the metabolism of these drugs in the liver—because of cytochrome P450—and causes the medication to exist in a higher level in the body and prolong its effects,3 which can be toxic or cause other problems, such as excess bleeding or hemorrhage.
CBD and sedatives
The exact relationship between sedatives and CBD is unknown, however, high doses of cannabinoids may have an unwanted additive effect, and the two likely should not be used together.
Sedatives are medications that suppress the central nervous system and are often prescribed to treat anxiety and sleeping disorders. Medications include benzodiazepines, such as alprazolam (Xanax) and lorazepam (Ativan), or sleep aids, like zolpidem (Ambien).
CBD and opioids
Opioids, such as hydrocodone/acetaminophen (Vicodin, Norco), oxycodone, (Oxycontin, Percocet) and fentanyl (Duragesic) are a powerful class of drugs used to treat pain that can be addictive. Research suggests that there is a relationship between the body’s opioids—endogenous, or naturally occurring opioids—and endocannabinoid system, although the exact mechanisms remain unknown.
One small study suggests that this interaction could help relieve pain and reduce opioid use when used together.4 However, more research should be done on this topic.
CBD oil use is on the rise, even becoming a staple for sale at retail drug stores in the form of creams, patches, and sprays. Ask your pharmacist or prescriber if you have any questions regarding the use of CBD oil and your other medications.
- Bornheim LM, Everhart ET, Li J, Correia MA. Characterization of cannabidiol-mediated cytochrome P450 inactivation. Biochem Pharmacol. 1993 Mar 24;45(6):1323-31. doi: 10.1016/0006-2952(93)90286-6. PubMed PMID: 8466552.
- Geffrey AL, Pollack SF, Bruno PL, Thiele EA. Drug-drug interaction between clobazam and cannabidiol in children with refractory epilepsy. Epilepsia. 2015 Aug;56(8):1246-51. doi: 10.1111/epi.13060. Epub 2015 Jun 26. PubMed PMID: 26114620.
- Grayson L, Vines B, Nichol K, Szaflarski JP; UAB CBD Program. An interaction between warfarin and cannabidiol, a case report. Epilepsy Behav Case Rep. 2017;9:10–11. Published 2017 Oct 12. doi:10.1016/j.ebcr.2017.10.001.
- Abrams DI, Couey P, Shade SB, Kelly ME, Benowitz NL. Cannabinoid-opioid interaction in chronic pain. Clin Pharmacol Ther. 2011 Dec;90(6):844-51. doi: 10.1038/clpt.2011.188. Epub 2011 Nov 2. PubMed PMID: 22048225.