Updated: Jan 2
In the context of the current CBD hype, many are wondering whether the use of CBD
can lead to drug interactions. In fact, cannabidiol (CBD) can affect the way drugs work.
The following article should help clarify this.
Cannabidiol (CBD) is a chemical compound (more specifically, a cannabinoid) found in
the flowers of the female hemp plant. In terms of chemical structure, CBD is similar to
the psychoactive tetrahydrocannabinol (THC). However, ingesting THC induces a high.
In its report from 2017/2018, the World Health Organization (WHO) summarized the
results of numerous studies on the tolerability and safety of cannabidiol (CBD) as a pure
substance. It states that CBD is well tolerated and poses no risk to general health.
WHAT ARE INTERACTIONS?
Doctors speak of interactions when two drugs affect each other after ingestion. This means that the medicines (or their active ingredients) can weaken or strengthen each other's effects.
This applies not only to medicines but also to substances of natural origin such as herbal preparations. Interactions can cause effects that are undesirable and can even
be harmful to health.
Research on CBD as a medicinal pure substance is still young. Although many researchers have already gained important insights into possible CBD drug interactions, these have not been fully researched. Therefore, in this article, we can only reproduce the interactions known so far.
CBD OILS: DRUG INTERACTIONS
The CBD interactions with drugs described in this article were observed in studies in
which medical CBD was used as a pure substance in high doses. CBD oil, on the other
hand, is an extract from hemp plants dissolved in a carrier oil (e.g. hemp oil). It is among the most well-known CBD products. The amount of CBD here is small and not comparable to medicinal CBD doses.
It is not known whether interactions between CBD oil and medicinal substances occur to the same extent. Because CBD oil is not a standardized product and can vary significantly in CBD quantity and quality. Nevertheless, caution is advised. Here, too, the application should not be carried out without consulting a doctor.
CBD INHIBITS THE ACTIVITY OF VARIOUS ENZYMES
Cannabidiol (CBD) can influence the activity of cytochrome P450 enzymes in the liver.
These play an important role in the metabolism, i.e. the breakdown of endogenous and
exogenous substances (e.g. active ingredients from medicines).
Both the effect and the tolerability of many medicinal substances depend decisively on
the enzymes of the cytochrome P450 family, which include the enzymes CYP2C19, CYP2D6, and CYP3A4.
CBD INTERACTIONS: DRUG EFFECT INCREASES
The acid inhibitor omeprazole and the anticonvulsant/neuroleptic drug risperidone
(Risperdal) require the enzyme CYP2C10. Here, a study showed that CBD inhibits this
enzyme, slowing down the breakdown of these drugs.
As a result, the drug may have a stronger effect than desired. In the worst case, it can
even lead to some serious side effects.
According to another study, CBD can also slow down the breakdown of the active
ingredients warfarin and diclofenac via the enzyme CYP2C9. While warfarin is used to
reduce blood clotting, diclofenac is used for pain and inflammation.
The inhibition of the enzyme by CBD also carries the risk that the effect and duration of
action of warfarin and diclofenac will increase.
INTERACTIONS WITH DRUGS: CBD EFFECT INCREASES
Taking the following drugs inhibits the activity of the enzyme CYP3A4:
Antifungal drugs such as ketoconazole or itraconazole (agents used to treat
Ritonavir (HIV protease inhibitor used to treat HIV infection)
Clarithromycin (antibiotics used to treat bacterial infections)
Taking CBD at the same time as medication can cause the liver to break down the CBD more slowly. As a result, the amount of CBD in the body can increase for a long time, so side effects such as sedation, sleep disorders, or increased susceptibility to infections can occur.
INTERACTIONS WITH DRUGS: CBD EFFECT DECREASES
Some drugs can speed up the activity of the CYP3A4 enzyme. These include:
Phenobarbital (strong sedative and sleep aid)
Rifampicin (an antibiotic used to treat mycobacterial infections)
If these active ingredients and medical cannabidiol (CBD) are taken at the same time,
there is a risk that CBD will be broken down more quickly. If medical CBD is used to
treat epilepsy, for example, the effect would be reduced if these drugs were taken at the
same time. This can have life-threatening consequences for a person with epilepsy.
OVERVIEW: CBD DRUG INTERACTIONS IN HUMANS
The intake of CBD and medicines must always be discussed with a doctor. In summary,
previous studies have shown that there can be interactions between CBD and the following medicinal substances:
Antiepileptics / Anticonvulsants
Sedatives and sleeping pills
Anti-inflammatory painkillers (such as diclofenac, ibuprofen, or naproxen)
Anticoagulants (blood thinners like warfarin)
Platelet aggregation inhibitors (e.g. acetylsalicylic acid (ASA) or clopidogrel)
CBD INTERACTION & DRUGS - IMPORTANT NOTE:
When we talk about sedatives and sleeping pills, we don't just mean prescription drugs.
There can also be an interaction between a herbal preparation and cannabidiol (CBD).
If taken at the same time, it would be quite possible for severe tiredness and drowsiness
to occur as an interaction/side effect.
CBD IN CANCER THERAPY
By activating or inhibiting various enzymes in the liver, CBD can affect how drugs work
in the body. So far, it is unclear whether and how CBD interacts with chemotherapeutic
agents. Science is still in its infancy here.
This is mainly because it is not ethical to give cancer patients different doses of CBD
over a longer period just to collect data.
Patients with cancer often receive not only chemotherapy drugs, but also many other
drugs. Since there is a risk that CBD can reduce or increase the effect of these preparations, the use of CBD should be avoided to be on the safe side.
CONCLUSION: CBD DRUG INTERACTIONS ARE POSSIBLE
The interactions of CBD with medicines have not yet been sufficiently researched. So
far, it is known that CBD influences various enzymes in the liver, which also require numerous other active ingredients for their effect on the body. Therefore, interactions of
CBD with medicinal substances cannot be ruled out in principle.
Taking medicines and CBD can strengthen or weaken the effect of the medicines.
Likewise, the amount of CBD in the body can increase, so that side effects can occur.
Such side effects can manifest themselves, for example, in tiredness, drowsiness,
nausea, vomiting, headache, and low blood pressure.
It is therefore particularly important that a combination of cannabidiol (CBD) and drugs
is discussed with a doctor in advance. This is especially true for patients who suffer
from epilepsy or who have to take blood thinners regularly.
In addition, it is not advisable to take medications such as neuroleptics, tranquilizers
and sleeping pills, antibiotics, and anti-inflammatory painkillers in combination with
As there are no studies on how CBD interacts with chemotherapy drugs, cancer patients should refrain from using CBD as a precaution. Because there is a risk that the chemotherapy drugs will lose their effectiveness.
HOW IS CBD COMPATIBLE WITH OTHER MEDICATIONS?
CBD and various medications such as neuroleptics, blood thinners, antibiotics, anti-
inflammatory painkillers, tranquilizers, and sleeping pills can influence each other's
effects. Therefore, a doctor should be consulted before taking it.
WHICH DRUGS ARE NOT COMPATIBLE WITH CBD?
Studies have shown that CBD can interact with neuroleptics, antibiotics, anti-
inflammatory painkillers, blood thinners, and tranquilizers, and sleep aids.
WHEN NOT TO TAKE CBD?
Pregnant and lactating women should not use CBD. In addition, patients with cancer
should avoid taking CBD as part of chemotherapy, as it is unclear to what extent CBD
influences the effectiveness of chemotherapeutic agents.
WHAT SIDE EFFECTS DOES CBD HAVE?
CBD rarely triggers side effects, and these are usually described as mild from
experience reports. Possible side effects include dry mouth, tiredness, vomiting/diarrhea, headache, loss of appetite, and low blood pressure.
Many people think CBD oil is not a medicine. They think of it more as a vitamin or a supplement, so they might not let their doctors know they’re using it. Although side effects are rare and minimal, Patients might not realize it can be potentially harmful with drug interactions. So, we always recommend speaking to your doctor to be safe. Studies have shown what amazing things CBD can do for ones health when taken in a safe way. Because we do not know everyone's health history we advise that when in doubt please consult your provider to be sure CBD is a good fit for you. Be Well!