CBD and Medicines

We are increasingly familiar with the way CBD works, but we know very little about the interaction between CBD and medicines.

Treating certain diseases with CBD is a relatively new phenomenon. There is still much to discover about the effects of the plant on the body and how it possibly reacts to other medications. The Dutch biochemist Steven Cassini therefore wrote the following article to make it clear to us how to deal with CBD when using certain medications.

Processing of medicines

Before a drug or natural substance disappears from the body, it often has to be metabolized first. The metabolism of drugs takes place in two phases: in phase I, reaction, the drug is made polar (water-soluble) by oxidation, reduction or hydrolysis. And in phase II the drug is conjugated, for example by acetylation or methylation.

This increases the water solubility and polarity of the medicine and can easily be excreted via the kidneys or the bile. Metabolism of medicines mainly takes place in the liver, but other organs such as the skin, the gastrointestinal tract, lungs, brains and kidneys can also be involved.

The cytochrome P450 system

The cytochrome P450 enzyme system (also abbreviated as CYP, P450 or CYP450) is a collection of 57 enzymes. Of these, 15 are important in the breakdown of various (foreign) substances such as medicines and toxins, but also in natural substances such as THC and other cannabinoids. These enzymes are not only important in the metabolism of medicines, natural substances and other foreign substances. But also play a role in physiological processes such as the oxidation of fatty acids.

Some natural substances may inhibit the activity of a CYP enzyme, increasing the plasma levels of drugs – or other natural substances that are metabolized via this enzyme.

The effects of the P450 enzyme system differs per person. This means that not everyone responds to the same dose of a medicine or natural substance. The rate at which a drug or natural substance is excreted from the body determines the serum concentration that occurs in the body, which in turn can influence the effect.

CBD can inhibit degradation of medicines

CBD can inhibit the P450 enzymes responsible for the breakdown of certain drugs. By inhibiting these enzymes, the medication is less well broken and the concentration of the drug in the blood can increase.

This can be an advantage under controlled circumstances, because you will then need less medication. However, under uncontrolled conditions it can be dangerous because it can cause the concentration of the drug in the blood to become too high and thereby increase the chance of serious side effects.

CBD strengthens or weakens the effect of THC

CBD can therefore enhance the effect of certain medicines. When CBD is taken before THC is taken, CBD also strengthens the effects of THC. The THC is broken down by the same group of P450 enzymes and the CBD therefore inhibits the degradation of THC.

However, if CBD is taken at least one hour after intake of THC, CBD reduces the psychoactive effect of THC, because the CBD then has an anti-psychotic effect.

CBD and chemotherapy

Most cytostatics (chemo) are also broken down by the same group of P450 enzymes. Since the fatal and therapeutic dose is very close to each other in certain cytostatics, it is not advisable to take high doses of CBD during chemotherapy, because the concentration of cytostatic agents in the blood can then be dangerously high.

CBD and medicines

In addition to the list below, there are many more medicines that are broken down by the P450 enzyme system. When using such medicines, it is therefore always wise to ask the treating physician whether the medicine you are using is being changed or broken down by the group P450 enzymes.

List of medicines that interact with CBD:

  • Anti epileptics
  • Antidepressants
  • Beta blockers
  • Antipsychotics
  • Benzodiazepines
  • Statins
  • Blood thinners
  • Steroids
  • NSAIDs (eg ibuprofen, diclofenac and naproxen)
  • Antibiotics

If this is the case, it is advisable to use CBD supplements carefully (especially at high doses) and to reduce the dosage of the medicine – in consultation with the treating physician – if necessary.