Be Prepared for Patients to Ask About CBD

Cannabidiol (CBD) products are moving into some pharmacies and mainstream retailers...not just smoke shops, dispensaries, etc.

CBD and THC are cannabinoids found in two varieties of the cannabis plant...marijuana and hemp. CBD doesn't cause a "high" like THC.

Hemp with 0.3% THC or less is no longer a federally controlled substance and is a legal source of CBD...after last year's Farm Bill.

But cannabis STATE laws vary. For example, cannabis is fully legal in California...but all forms are illegal in Idaho.

FDA regulations add to the confusion. They say CBD can't be sold as a supplement...since it was first approved as an Rx drug (Epidiolex). But CBD is allowed in hemp-derived "cosmetics"...creams, lotions, etc.

This leaves a lot of murkiness with CBD...especially with orals, tinctures, foods, etc...and enforcement is spotty.

So far, the most conclusive evidence is with Epidiolex...a purified CBD solution approved for two rare and severe seizure disorders.

Emphasize that there's not good evidence yet to support popular CBD claims...such as relieving chronic pain, anxiety, or insomnia.

And the variety of CBD products leaves many unknowns about their safety, quality, dosing, etc.

In general, recommend avoiding CBD in pregnant or breastfeeding women...and lean away from it in patients taking multiple meds.

Educate that CBD may cause drowsiness, diarrhea, etc...and using it with CNS depressants (benzos, opioids, etc) may worsen sedation.

Be aware of many potential interactions. For example, CBD inhibits CYP2C8, 2C9, and 2C19...and might raise levels of meds such as amitriptyline, valproic acid, and warfarin. Or CBD levels might be increased by CYP3A4 inhibitors, such as clarithromycin.

Plus high CBD doses are linked to elevated liver function tests. Explain most urine drug tests check for THC...not CBD. But high CBD doses with trace amounts of THC...or impure products...could lead to a positive THC test.

If patients plan to try CBD, suggest checking the product for a "certificate of analysis" from an independent lab. This doesn't confirm safety or efficacy...but shows levels of CBD, THC, and contaminants.

Dive deeper with our chart, Comparison of Cannabinoids...and access our Natural Medicines for more on efficacy, safety, and interactions.

Key References:

-www.fda.gov/NewsEvents/PublicHealthFocus/ucm421168.htm#othercbdapproved (05-16-19)

-Health Effects of Cannabis and Cannabinoids: National Academies Press (US); 2017

-Can Fam Physician 2018;64(2):111-20

Pharmacist's Letter. June 2019, No. 350604