What Experts are saying Cannabidiol “CBD”. 

What is it?

Cannabidiol is a chemical in the Cannabis sativa plant, also known as marijuana or hemp. Over 80 chemicals, known as cannabinoids, have been identified in the Cannabis sativa plant. While delta-9-tetrahydrocannabinol (THC) is the major active ingredient in marijuana, cannabidiol is also obtained from hemp, which contains only very small amounts of THC.

The passage of the 2018 Farm Bill made it legal to sell hemp and hemp products in the U.S. But that doesn’t mean that all hemp-derived cannabidiol products are legal. Since cannabidiol has been studied as a new drug, it can’t be legally included in foods or dietary supplements. Also, cannabidiol can’t be included in products marketed with therapeutic claims. Cannabidiol can only be included in “cosmetic” products and only if it contains less than 0.3% THC. But there are still products labeled as dietary supplements on the market that contain cannabidiol. The amount of cannabidiol contained in these products is not always reported accurately on the product label.

Cannabidiol is most commonly used for seizure disorder (epilepsy). It is also used for anxiety, pain, a muscle disorder called dystonia, Parkinson disease, Crohn disease, and many other conditions, but there is no good scientific evidence to support these uses.

How effective is CBd?

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for CANNABIDIOL (CBD) are as follows:

CBD is Likely effective for …

• Seizure disorder (epilepsy). A specific cannabidiol product (Epidiolex, GW Pharmaceuticals) has been shown to reduce seizures in adults and children with various conditions that are linked with seizures. This product is a prescription drug for treating seizures caused by Dravet syndrome or Lennox-Gastaut syndrome. It has also been shown to reduce seizures in people with tuberous sclerosis complex, Sturge-Weber syndrome, febrile infection-related epilepsy syndrome (FIRES), and specific genetic disorders that cause epileptic encephalopathy. But it’s not approved for treating these other types of seizures.

CBD Insufficient evidence to rate effectiveness for…

• Bipolar disorder. Early reports show that taking cannabidiol does not improve manic episodes in people with bipolar disorders.
• A type of inflammatory bowel disease (Crohn disease). Early research shows that taking cannabidiol does not reduce disease activity in adults with Crohn disease.
• Diabetes. Early research shows that taking cannabidiol does not improve blood glucose levels, blood insulin levels, or HbA1c in adults with type 2 diabetes.
• A movement disorder marked by involuntary muscle contractions (dystonia). Early research suggests that taking cannabidiol daily for 6 weeks might improve dystonia by 20% to 50% in some people. Higher quality research is needed to confirm this.
• An inherited condition marked by learning disabilities (fragile- X syndrome). Early research found that applying cannabidiol gel might reduce anxiety and improve behavior in patients with fragile X syndrome.
• A condition in which a transplant attacks the body (graft-versus-host disease or GVHD). Graft-versus-host disease is a complication that can occur after a bone marrow transplant. In people with this condition, donor cells attack the person’s own cells. Early research shows that taking cannabidiol daily starting 7 days before bone marrow transplant and continuing for 30 days after transplant can extend the time it takes for a person to develop GVHD.
• An inherited brain disorder that affects movements, emotions, and thinking (Huntington disease). Early research shows that taking cannabidiol daily does not improve symptoms of Huntington’s disease.
• Insomnia. Early research suggests that taking 160 mg of cannabidiol before bed improves sleep time in people with insomnia. However, lower doses do not have this effect. Cannabidiol also does not seem to help people fall asleep and might reduce the ability to recall dreams.
• Multiple sclerosis (MS). There is inconsistent evidence on the effectiveness of cannabidiol for symptoms of multiple sclerosis. Some early research suggests that using a cannabidiol spray under the tongue might improve pain and muscle tightness in people with MS. However, it does not appear to improve muscle spasms, tiredness, bladder control, the ability to move around, or well-being and quality of life.
• Withdrawal from heroin, morphine, and other opioid drugs. Early research shows that taking cannabidiol for 3 days reduces cravings and anxiety in people with heroin use disorder that are not using heroin or any other opioid drugs.
• Parkinson disease. Some early research shows that taking cannabidiol daily for 4 weeks improves psychotic symptoms in people with Parkinson disease and psychosis.
• Schizophrenia. Research on the use of cannabidiol for psychotic symptoms in people with schizophrenia is conflicting. Some early research suggests that taking cannabidiol four times daily for 4 weeks improves psychotic symptoms and might be as effective as the antipsychotic medication amisulpride. However, other early research suggests that taking cannabidiol for 14 days is not beneficial. The conflicting results might be related to the cannabidiol dose used and duration of treatment.
• Quitting smoking. Early research suggests that inhaling cannabidiol with an inhaler for one week might reduce the number of cigarettes smoked by about 40% compared to baseline.
• A type of anxiety marked by fear in some or all social settings (social anxiety disorder). Some early research shows that taking cannabidiol 300 mg daily does not improve anxiety during public speaking in people with social anxiety disorder. However, other early research in people with social anxiety disorder suggests that taking a higher dose (400-600 mg) may improve anxiety associated with public speaking or medical imaging testing. Also, some research in people who do not have social anxiety disorder shows that taking cannabidiol 300 mg might reduce anxiety during public speaking.
• Other conditions.

More evidence is needed to rate the effectiveness of cannabidiol for these uses.

How does CBD work?

Cannabidiol has effects on the brain. The exact cause for these effects is not clear. However, cannabidiol seems to prevent the breakdown of a chemical in the brain that affects pain, mood, and mental function. Preventing the breakdown of this chemical and increasing its levels in the blood seems to reduce psychotic symptoms associated with conditions such as schizophrenia. Cannabidiol might also block some of the psychoactive effects of delta-9-tetrahydrocannabinol (THC). Also, cannabidiol seems to reduce pain and anxiety.

Are there safety concerns for CBD?

When taken by mouth: Cannabidiol is POSSIBLY SAFE when taken by mouth or sprayed under the tongue appropriately. Cannabidiol in doses of up to 300 mg daily have been taken by mouth safely for up to 6 months. Higher doses of 1200-1500 mg daily have been taken by mouth safely for up to 4 weeks. A prescription cannabidiol product (Epidiolex) is approved to be taken by mouth in doses of up to 10-20 mg/kg daily. Cannabidiol sprays that are applied under the tongue have been used in doses of 2.5 mg for up to 2 weeks.

Some reported side effects of cannabidiol include dry mouth, low blood pressure, light headedness, and drowsiness. Signs of liver injury have also been reported in some patients, but this is less common.

When applied to the skin: There isn’t enough reliable information to know if cannabidiol is safe or what the side effects might be.

Special precautions & warnings:

Pregnancy and breast-feeding: Cannabidiol is POSSIBLY UNSAFE to use if you are pregnant or breast feeding. Cannabidiol products can be contaminated with other ingredients that may be harmful to the fetus or infant. Stay on the safe side and avoid use.

Children: A prescription cannabidiol product (Epidiolex) is POSSIBLY SAFE when taken by mouth daily. The most common dose used is 10 mg/kg daily. Higher doses of 15-20 mg/kg daily may be used in some children, but these higher doses are more likely to cause side effects. This product is approved for use in certain children 2 years of age and older, but has been used in children as young as 1 year of age.

Liver disease: People with liver disease may need to use lower doses of cannabidiol compared to healthy patients.

Parkinson disease: Some early research suggests that taking high doses of cannabidiol might make muscle movement and tremors worse in people with Parkinson disease.

Are there CBD  interactions with medications?

MajorDo not take this combination.Clobazam (Onfi)Clobazam is changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down clobazam. This might increase the effects and side effects of clobazam.ValproateValproic acid can cause liver injury. Taking cannabidiol with valproic acid might increase the chance of liver injury. Discontinuation or reduction in dosage of cannabidiol and/or valproic acid might be needed.ModerateBe cautious with this combination.Brivaracetam (Briviact)Brivaracetam is changed and broken down by the body. Cannabidiol might decrease how quickly the body breaks down brivaracetam. This might increase levels of brivaracetam in the body.Eslicarbazepine (Aptiom)Eslicarbazepine is changed and broken down by the body. Cannabidiol might decrease how quickly the body breaks down eslicarbazepine. This might increase levels of eslicarbazepine in the body by a small amount.Everolimus (Zostress)Everolimus is changed and broken down by the body. Cannabidiol might decrease how quickly the body breaks down everolimus. This might increase levels of everolimus in the body.Medications changed by the liver (Cytochrome P450 1A1 (CYP1A1) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include chlorzoxazone (Lorzone) and theophylline (Theo-Dur, others).Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include amitriptyline (Elavil), haloperidol (Haldol), ondansetron (Zofran), propranolol (Inderal), theophylline (Theo-Dur, others), verapamil (Calan, Isoptin, others), and others.Medications changed by the liver (Cytochrome P450 1B1 (CYP1B1) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include theophylline (Theo-Dur, others), omeprazole (Prilosec, Omesec), clozapine (Clozaril, FazaClo), progesterone (Prometrium, others), lansoprazole (Prevacid), flutamide (Eulexin), oxaliplatin (Eloxatin), erlotinib (Tarceva), and caffeine.Medications changed by the liver (Cytochrome P450 2A6 (CYP2A6) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include nicotine, chlormethiazole (Heminevrin), coumarin, methoxyflurane (Penthrox), halothane (Fluothane), valproic acid (Depacon), disulfiram (Antabuse), and others.Medications changed by the liver (Cytochrome P450 2B6 (CYP2B6) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include ketamine (Ketalar), phenobarbital, orphenadrine (Norflex), secobarbital (Seconal), and dexamethasone (Decadron).Medications changed by the liver (Cytochrome P450 2C19 (CYP2C19) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include proton pump inhibitors including omeprazole (Prilosec), lansoprazole (Prevacid), and pantoprazole (Protonix); diazepam (Valium); carisoprodol (Soma); nelfinavir (Viracept); and others.Medications changed by the liver (Cytochrome P450 2C8 (CYP2C8) substrates)Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.
Some medications changed by the liver include amiodarone (Cordarone), carbamazepine (Tegretol), chloroquine (Aralen), diclofenac (Voltaren), paclitaxel (Taxol), repaglinide (Prandin) and others.Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac (Cataflam, Voltaren), ibuprofen (Motrin), meloxicam (Mobic), and piroxicam (Feldene); celecoxib (Celebrex); amitriptyline (Elavil); warfarin (Coumadin); glipizide (Glucotrol); losartan (Cozaar); and others.Medications changed by the liver (Cytochrome P450 2D6 (CYP2D6) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include amitriptyline (Elavil), codeine, desipramine (Norpramin), flecainide (Tambocor), haloperidol (Haldol), imipramine (Tofranil), metoprolol (Lopressor, Toprol XL), ondansetron (Zofran), paroxetine (Paxil), risperidone (Risperdal), tramadol (Ultram), venlafaxine (Effexor), and others.Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include alprazolam (Xanax), amlodipine (Norvasc), clarithromycin (Biaxin), cyclosporine (Sandimmune), erythromycin, lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), verapamil (Calan, Isoptin) and many others.Medications changed by the liver (Cytochrome P450 3A5 (CYP3A5) substrates)

Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. In theory, using cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before using cannabidiol, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications changed by the liver include testosterone, progesterone (Endometrin, Prometrium), nifedipine (Adalat CC, Procardia XL), cyclosporine (Sandimmune), and others.Medications changed by the liver (Glucuronidated drugs)Some medications are changed and broken down by the liver. Cannabidiol might decrease how quickly the liver breaks down some medications. Taking cannabidiol along with some medications that are broken down by the liver might increase the effects and side effects of these medications.
Some of these medications changed by the liver include acetaminophen (Tylenol, others) and oxazepam (Serax), haloperidol (Haldol), lamotrigine (Lamictal), morphine (MS Contin, Roxanol), zidovudine (AZT, Retrovir), and others.Medications that decrease the breakdown of other medications by the liver (Cytochrome P450 2C19 (CYP2C19) inhibitors)Cannabidiol is broken down by the liver. Some medications might decrease how quickly the liver breaks down cannabidiol. Taking cannabidiol along with these medications might increase the effects and side effects of cannabidiol.
Some medications that might decrease the breakdown cannabidiol in the liver include cimetidine (Tagamet), fluvoxamine (Luvox), omeprazole (Prilosec); ticlopidine (Ticlid), topiramate (Topamax), and others.Medications that decrease the breakdown of other medications in the liver (Cytochrome P450 3A4 (CYP3A4) inhibitors)Cannabidiol is broken down by the liver. Some medications might decrease how quickly the liver breaks down cannabidiol. Taking cannabidiol along with these medications might increase the effects and side effects of cannabidiol.
Some medications that might decrease how quickly the liver breaks down cannabidiol include amiodarone (Cordarone), clarithromycin (Biaxin), diltiazem (Cardizem), erythromycin (E-mycin, Erythrocin), indinavir (Crixivan), ritonavir (Norvir), saquinavir (Fortovase, Invirase), and many others.Medications that increase breakdown of other medications by the liver (Cytochrome P450 3A4 (CYP3A4) inducers)Cannabidiol is broken down by the liver. Some medications might increase how quickly the liver breaks down cannabidiol. Taking cannabidiol along with these medications might decrease the effects of cannabidiol.
Some of these medicines include carbamazepine (Tegretol), phenobarbital, phenytoin (Dilantin), rifampin, rifabutin (Mycobutin), and others.Medications that increase the breakdown of other medications by the liver (Cytochrome P450 2C19 (CYP2C19) inducers)Cannabidiol is broken down by the liver. Some medications might increase how quickly the liver breaks down cannabidiol. Taking cannabidiol along with these medications might decrease the effects of cannabidiol.
Some medications that might increase the breakdown of cannabidiol in the liver include carbamazepine (Tegretol), prednisone (Deltasone), and rifampin (Rifadin, Rimactane).Rufinamide (Banzel)Rufinamide is changed and broken down by the body. Cannabidiol might decrease how quickly the body breaks down rufinamide. This might increase levels of rufinamide in the body by a small amount.Sedative medications (CNS depressants)

Cannabidiol might cause sleepiness and drowsiness. Medications that cause sleepiness are called sedatives. Taking cannabidiol along with sedative medications might cause too much sleepiness.

Some sedative medications include benzodiazepines, pentobarbital (Nembutal), phenobarbital (Luminal), secobarbital (Seconal), thiopental (Pentothal), fentanyl (Duragesic, Sublimaze), morphine, propofol (Diprivan), and others.Tacrolimus (Prograf)Tacrolimus is changed and broken down by the body. Cannabidiol might decrease how quickly the body breaks down tacrolimus. This might increase levels of tacrolimus in the body.Topiramate (Tompamax)Topiramate is changed and broken down by the body. Cannabidiol might decrease how quickly the body breaks down topiramate. This might increase levels of topiramate in the body by a small amount.ZonisamideZonisamide is changed and broken down by the body. Cannabidiol might decrease how quickly the body breaks down zonisamide. This might increase levels of zonisamide in the body by a small amount.

Are there interactions with herbs and supplements?

Herbs and supplements with sedative propertiesCannabidiol can cause sleepiness or drowsiness. Using it along with other herbs and supplements that have the same effect might cause too much sleepiness. Some of these herbs and supplements include calamus, California poppy, catnip, hops, Jamaican dogwood, kava, L-tryptophan, melatonin, sage, SAMe, St. John’s wort, sassafras, skullcap, and others.

Are there interactions with foods?

Fats and fat-containing foodsTaking cannabidiol with a meal that is high in fat increases the amount of cannabidiol that is absorbed by the body. This might increase the effects and side effects of cannabidiol.

What dose is used?

The following doses have been studied in scientific research:

ADULTS

BY MOUTH:

• For epilepsy: A prescription cannabidiol product (Epidiolex) has been used. The recommended starting dose is usually 2.5 mg/kg twice daily (5 mg/kg/day). After one week the dose can be increased to 5 mg/kg twice daily (10 mg/kg/day). If the person doesn’t respond to this dose, the maximum recommended is 10 mg/kg twice daily (20 mg/kg/day). In some research, higher doses of up to 50 mg/kg daily have been used. There is no strong scientific evidence that nonprescription cannabidiol products are beneficial for epilepsy.

CHILDREN

BY MOUTH:

• For epilepsy: A prescription cannabidiol product (Epidiolex) has been used. The recommended starting dose is usually 2.5 mg/kg twice daily (5 mg/kg/day). After one week the dose can be increased to 5 mg/kg twice daily (10 mg/kg/day). If the person doesn’t respond to this dose, the maximum recommended is 10 mg/kg twice daily (20 mg/kg/day). In some research, higher doses of up to 50 mg/kg daily have been used. There is no strong scientific evidence that nonprescription cannabidiol products are beneficial for epilepsy.

Other names

2-[(1R,6R)-3-Methyl-6-prop-1-en-2-ylcyclohex-2-en-1-yl]-5-pentylbenzene-1,3-diol, CBD.

Methodology

To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.