Cannabidiol (CBD) is a non-intoxicating compound derived from the cannabis plant used as a supplement. Antibiotics are prescription medications designed to eliminate or inhibit bacterial growth to treat infections. When CBD and antibiotics are taken together, there is a risk of pharmacological interaction because both are processed by the body’s drug-metabolizing system. This interference can alter the intended effects of both substances. Understanding this interaction is important for anyone using CBD while undergoing antibiotic treatment.
The Shared Metabolic Pathway
The interaction between CBD and many antibiotics centers on the liver’s Cytochrome P450 (CYP450) enzyme system. This group of enzymes breaks down over 60% of all medicines and foreign compounds in the body. CBD is metabolized by several of these enzymes, notably CYP3A4 and CYP2C19, for elimination.
CBD also acts as a competitive inhibitor, blocking the enzymes’ ability to process other substances. When CBD is present, it occupies the active sites of the CYP450 enzymes. This competition slows the metabolic rate for any other drug that shares the same pathway, causing potential drug-drug interactions.
Increased Risk of Antibiotic Side Effects
The inhibition of CYP450 enzymes by CBD directly impacts how the body processes antibiotic medication. When CBD slows the metabolism of the antibiotic, the drug is cleared from the bloodstream slower than intended. This delay leads to a higher concentration of the antibiotic circulating in the body for an extended period.
This elevated concentration can push the drug level beyond its therapeutic window, making side effects more likely. Antibiotics relying heavily on the CYP3A4 pathway, such as macrolides like clarithromycin and erythromycin, are susceptible to this effect. High levels of antibiotics increase the risk of specific toxicities, such as gastrointestinal distress, liver strain, or neurotoxicity.
Changes to Cannabidiol Efficacy and Side Effects
The interaction is reciprocal; certain antibiotics can also significantly affect the concentration of CBD in the body. Some antibiotics are potent inhibitors of the same CYP450 enzymes that metabolize CBD. If the antibiotic inhibits CYP3A4 or CYP2C19, it slows the breakdown of CBD.
This combined inhibitory effect leads to elevated levels of CBD in the bloodstream. The resulting higher concentration may increase the likelihood and intensity of common CBD side effects. These side effects include drowsiness, fatigue, dry mouth, or diarrhea.
Practical Safety Considerations and Medical Guidance
Anyone taking an antibiotic who is also using CBD must inform their healthcare provider about all supplements consumed. This disclosure allows medical professionals to assess the specific risk based on the prescribed antibiotic and the CBD dose. Never discontinue a prescribed antibiotic regimen without medical guidance, even if an interaction is suspected.
One strategy to manage the risk is to temporarily stop using CBD for the duration of the antibiotic course. If cessation is not possible, a healthcare provider might suggest reducing the CBD dosage or spacing the doses several hours apart to minimize competition for liver enzymes. Monitoring for any unusual or increased side effects from either substance is also a safety measure during co-administration.