It is no news that medications and supplements may interact inside your body when you take them at the same time. This is actually the reason behind your doctors pointedly asking you what medications you are currently taking. They are not being nosey; doctors need to know if the medication they might prescribe you will interact adversely with something else that you are already taking.
Cannabis is a complex plant, with hundreds and hundreds of chemicals and over 100 distinct cannabinoids. CBD is the second most common cannabinoid found in cannabis. Research states that cannabidiol shows evidence of potential health benefits for a wide range of conditions. However, as CBD becomes more mainstream, a key question comes to mind, “How will CBD interact with current medication?” Many doctors and researchers urge individuals who are using CBD medically or recreationally to be cautious when it comes to mixing it with other prescriptions. It is advised to consult with healthcare providers about possible interactions.
The key to understanding how CBD and other medications can adversely interact is to understand how the body metabolizes the different substances. Metabolism is the chemical process in which the body breaks down the substances you put into it, including both food and drugs. Metabolism consists of two distinct processes, anabolism, and catabolism, the buildup of substances and the breakdown of substances. Both of these processes are based on biochemical reactions. Enzymes are the main catalysts inside our bodies that cause biochemical reactions. These chemicals mix with the substances that we ingest and cause chemical reactions that allow metabolism to happen.
When you take a medication or any other substance, your body has to metabolize it or break it down. Drug metabolism happens throughout the body, in the gut, but the liver also does a big part of the job. There is an enzyme that metabolizes about 50% and 60% of all clinically-prescribed medications. A family of enzymes called cytochrome P450 (CYP450) is involved with the breakdown of various drugs and foreign substances, so they can be no longer toxic. These substances or drugs are then excreted out of the body through urine, feces, or sweat. Yet, some medications or substances affect CYP450 in different ways by either slowing or speeding up drug metabolism. This change in metabolism rate can change how your body processes the medications or supplements you take — hence a drug interaction.
CBD also has the ability to interact directly with the CYP system in the liver. Research shows that the way in which CBD does is by binding to the site where the enzyme activity occurs, then acting as a “competitive inhibitor”, displacing its chemical competitors. Thus, it prevents the CYP system from metabolizing other compounds.
According to the Indiana University Department of Medicine, some pharmaceutical drugs and medications which can be contraindicated for use with CBD include steroids and corticosteroids, HMG CoA reductase inhibitors, Calcium channel blockers, Antihistamines, Prokinetics, HIV antivirals, Immune modulators, Benzodiazepines, Antiarrhythmics, Antibiotics, Anesthetics, Antipsychotics, Antidepressants, Anticonvulsants / Anti-Seizure Medications, Beta-blockers, Proton-Pump Inhibitors (PPIs), Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), Angiotensin II Blockers, Oral Hypoglycemic Agents, Sulfonylureas.
Possible drug-drug interactions between CBD and other medications
CBD and Clobazam
Clobazam is a standard antiepileptic drug that is often used for the management of seizures and epilepsy. On the other hand, CBD has been proven effective in treating drug-resistant epilepsy in children and adults. CBD is often administered with clobazam for the treatment of epilepsy, and therefore, a concern was raised regarding the potential interaction between both drugs. However, available evidence suggests minimal interaction between both drugs with no harmful side effects of their concurrent use. That being said, the levels of clobazam in the blood should be monitored on a monthly basis to prevent the occurrence of clobazam toxicity.
The interaction between CBD and other antiepileptic drugs was also investigated; however, no significant association was noted between them.
CBD and Tacrolimus
Tacrolimus is a drug that is often used in patients who are undergoing organ transplantation. A recent research study found that a patient who was treated with CBD for his epileptic condition was also receiving tacrolimus at the same time. The treating physician noted that the levels of tacrolimus in the blood were triple the normal level without CBD use. Therefore, it was highlighted that CBD could lead to detrimental effects in patients who are taking tacrolimus and are undergoing organ transplantation.
CBD and Methadone
Methadone is a drug that is commonly used in opioid dependence. It is also used for pain management. This drug is metabolized by cytochrome P3A4, which is inhibited by CBD. This leads to a dramatic increase in the level of methadone in the blood, which could lead to toxicity and side effects.
Therefore, CBD should be carefully used when you are on other drugs.