THC, the psychoactive ingredient in cannabis, interacts with nearly 400 prescription drugs and CBD (cannabidiol) interacts with more than 540. While generally considered safe, CBD can cause drowsiness, lightheadedness, nausea, diarrhea, dry mouth and, in rare cases, liver damage. Taking CBD with other medications that have similar side effects may increase the risk of developing unwanted symptoms or toxicity. In other words, taking CBD at the same time as over-the-counter or prescription drugs and substances that cause drowsiness, such as opioids, benzodiazepines (such as Xanax or Ativan), antipsychotics, antidepressants, antihistamines (such as Benadryl), or alcohol, can cause increased sleepiness, fatigue, and possibly accidental falls and accidents while driving.
You can also experience increased sedation and tiredness when consuming certain herbal supplements, such as kava, melatonin and St. Taking CBD with stimulants (such as Adderall) may cause a decrease in appetite, while taking it with metformin, a medication for diabetes, or with certain medications for heartburn (such as Prilosec), it may increase the risk of diarrhea. A pharmacist is a great resource to help you learn about a possible interaction with a supplement, an herbal product (many of which have their own drug interactions), or an over-the-counter or prescription drug. The researchers also warned that, while the list can be used as a starting point for identifying possible drug interactions with marijuana or CBD oil, plant-based cannabinoid products can offer highly variable cannabinoid concentrations (unlike the prescription cannabinoid drugs regulated by the FDA mentioned above) and may contain many other compounds that may increase the risk of unwanted drug interactions.
These include the known side effects of CBD, but also unwanted interactions with supplements, herbal products, and over-the-counter (OTC) and prescription drugs. Edible foods take longer to be absorbed and are less likely to produce a high-concentration peak, although they may eventually reach levels high enough to cause problems or interact with other medications. The altered concentration, in turn, may result in the medication not working or an increased risk of side effects. That means that there is a risk that marijuana will dangerously increase the effects of some prescription drugs or cause other drugs to be eliminated by the body so quickly that they are useless, said lead researcher Philip Lazarus.
People who are thinking of consuming CBD products should always mention their use to their doctor, especially if they are taking other medications or have underlying medical conditions, such as liver disease, kidney disease, epilepsy, heart problems, a weakened immune system, or if they are taking medications that can weaken the immune system (such as anticancer drugs). Topical formulations, such as creams and lotions, may not be absorbed or reach the blood in sufficient quantity to interact with other medications, although there is very little information on the amount of CBD that ultimately passes into the blood.