by Nick Marshall
Analogs of many plant cannabinoids are produced naturally in the body and known as endocannabinoids. Therefore, cannabidiol (CBD), one of the most prevalent cannabinoids in hemp, should not pose a threat by itself. This is one of the reasons CBD oil has become a popular supplement for treating a variety of conditions, from anxiety to inflammation. Where there is cause for caution, however, is when combining CBD with other medicines or chemicals. The science is complex, but CBD can affect the activity of some medications in the body, either rendering vital drugs less effective, or interfering with the body’s normal modes of metabolizing these substances.
CBD Interactions with Over-the-Counter Medication
At the moment, regulation and control of CBD products can be inconsistent and confusing. The FDA has approved only one CBD product, the epilepsy medication Epidiolex. Without clear guidance, the tendency for users is to self-dose, which usually presents few dangers as long as the product is THC-free. However, anyone taking over-the-counter medications or supplements should check with their doctor before incorporating CBD into their regimen. CBD can inhibit the metabolization of some antihistamines and prokinetics (commonly used to treat excessive gastric acid). As a result, these medications might not produce the desired effect.
CBD and Prescription Drugs–The Importance of the P450 Enzyme
So far, so simple. Matters become more complicated, however, when it comes to taking CBD in combination with some common prescription medications. This is because almost a quarter of all drugs are metabolized in the body by the CYP3A4 and CYP2D6 enzymes, and that includes THC and CBD. These are just two of the enzymes in the P450 family, the route by which so many medications are broken down in the liver and flushed out of the body. CBD inhibits the functioning of the P450 enzyme. As a result, concentrations of these medications could exceed recommended levels.
Common medications metabolized by the P450 family include some of the following:
- Opioids (including codeine, hydrocodone and oxycodone).
- Epilepsy medications
The National Institutes of Health specifically advises against taking CBD with two common epilepsy medications, Clobazam and valproic acid. CBD can cause irritability, drowsiness and seizures combined with the former, and liver damage with the latter.
CBD can cause pharmacodynamic reactions with certain benzodiazepines, opioids and phenobarbital, with symptoms such as increased sedation, irritability and nausea. Taking CBD is also unwise with certain anticoagulants used to reduce the risk of blood clotting. Because CBD increases blood levels of the anti-clotting medication coumadin, there is an increased risk of bleeding.
The range of interactions involving the P450 enzymes is so broad that no single rule could cover all the possible side effects and metabolic complications. In some cases, taking medication with CBD may reduce or nullify the effects of an important drug; in others, it may cause drug levels to accumulate in the liver and the blood. Interestingly, CBD is not the only culprit in this respect. Both grapefruit and St. John’s wort have a similar effect on P450 enzymes, one of the reasons why doctors typically recommend avoiding them during a course of treatment.
CBD in Combination with Plants
By itself, CBD does not cause any noticeable side effects. Only cannabis supplements that contain THC levels above 0.3% produce intoxication and psychoactive effects. But CBD can intensify the sedative properties of some common plants and botanicals that are already known for their mildly intoxicating effects. The list includes catnip, hops, kava, melatonin, sage and St. John’s wort. Bear in mind, however, that this may be a bonus when the botanical is taken to address the same symptoms that CBD often treats, such as insomnia or anxiety.
The safest way to integrate CBD into pain management is with the support and guidance of medical professionals. They can advise on CBD dosage and, if necessary, adjust the dosage of complementary medicine (often reducing it). While there is a lack of definitive evidence at the moment, a strong and tantalizing hypothesis exists that CBD could actually become a dependable and effective substitute for many prescription medications on the above list, with none of the harmful side effects. Given the growing opioid crisis in America and elsewhere, CBD would be a welcome alternative to prescription painkillers, with no risk of addiction or dependency.
Nick Marshall is a UK-based, independent journalist and copywriter helping global food, travel, lifestyle and technology brands tell their story.