Cannabinoids May Affect Activity of Other Pharmaceuticals

As CBD products have grown in popularity and other cannabinoid products have become legal in some states, amputees who struggle with pain may have turned to them for relief. But it is important to be aware of potential interactions with other medications. Cannabinoid-containing products may alter the effects of some prescription drugs, according to Penn State College of Medicine researchers. They published information that could help medical professionals make safe prescribing choices for their patients who use cannabinoid products.

Kent Vrana, PhD, professor and chair of pharmacology at the College of Medicine, and Paul Kocis, PharmD, a pharmacist at Penn State Health Milton S. Hershey Medical Center, compiled a list of 57 medications that may not function as intended when used with medical cannabinoids, CBD oil (hemp oil), and medical or recreational marijuana.

The medications on the list have a narrow therapeutic index, meaning they are prescribed at specific doses—enough to be effective, but not enough to cause harm. Vrana says it’s important for medical professionals to consider the list when prescribing medical cannabinoids and how they may affect other medications a patient is taking.

The list contains a variety of drugs from heart medications to antibiotics and antifungals. As one example, researchers identified warfarin, a common anticoagulant that prevents harmful blood clots from forming, as having a potential drug-drug interaction with cannabinoid products. Often prescribed for patients with atrial fibrillation or following cardiac valve replacement, the drug has a narrow therapeutic index, and Vrana cautions that medical professionals consider this potential drug-drug interaction when prescribing warfarin to patients on prescription cannabinoids or prescribing cannabinoids to a patient taking warfarin.

The researchers say that medical professionals should also consider patient use of CBD oil products and medical and recreational marijuana when using or prescribing drugs on the identified list. Most of those products lack government regulation, and there is little to no prescribing or drug-drug interaction information for those products.

Vrana advises patients to be honest with their healthcare providers about their use of cannabinoid products—from over-the-counter products to recreational marijuana. He says that doing so can help ensure the safe and effective use of prescribed medications.

This article was adapted from information provided by Penn State College of Medicine.


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57 medications that may not function as intended when used with medical cannabinoids139 medications that could have a potential drug-drug interaction with a cannabinoid

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