Marijuana and prescription drugs: a dangerous combination

Each time you pick up a prescription, your pharmacist might ask if you have any questions about how to take your medication or advise you about which other prescriptions might cause a dangerous interaction. Now, several local pharmacists, including Seung Oh, the pharmacy supervisor at Sharp Rees-Stealy Santee Medical Center, want you to also be cautioned that your medications could lead to potentially harmful reactions when combined with using marijuana, also known as cannabis.

In San Diego, the county records 29 marijuana-related ER visits every day. Marijuana-related medical conditions include cannabis-induced psychosis, severe vomiting, cardiac and pulmonary complications, contamination, allergies, addiction, and withdrawal. Additionally, marijuana and prescription drug interactions are increasing.

In response, 17 local pharmacies have come together to spread the word about the San Diego Marijuana Prevention Initiative, a program created to provide much-needed consumer information about marijuana and possible interactions with prescription medications.

Which drugs interact with marijuana?
According to Oh, he and the other pharmacists are neither advocating nor discouraging the use of marijuana. However, they want the public to know that just as pairing grapefruit with statins can cause a dangerous interaction, THC and CBD — chemicals found in marijuana and cannabis products, such as gummies and other edibles — can interact with prescription medications and lead to serious side effects.

These side effects can include bleeding complications, increased drowsiness, reduced heart rate and breathing rate, extreme confusion and memory loss, poor judgment, and aggression. THC, the psychoactive ingredient in cannabis, interacts with nearly 400 prescription medications, and CBD (cannabidiol) interacts with more than 540.

Common types of drugs that can have dangerous interactions with marijuana include:

• Sedatives — such as Ambien, Lunesta and Benadryl

• Anti-anxiety medications — such as Xanax, Valium and Librium

• Antidepressants — such as Zoloft, Prozac and Lexapro

• Pain medications — such as codeine, Percocet and Vicodin

• Anticonvulsants (seizure medications) — such as Tegretol, Topamax and Depakene

• Anticoagulants (blood thinners) — such as Coumadin, Plavix and heparin

“Currently very few — if any — pharmacies in San Diego provide information on drug interactions with marijuana products, but it is standard practice to include prescription label warnings about possible interactions with a number of other products,” Oh says. “While marijuana is legal for adults over age 21 in California, and medically recommended in some cases, it is rare to find consumer protections regarding combining prescriptions with marijuana.”

How the San Diego Marijuana Prevention Initiative will help
To ensure that San Diegans know of the dangers of marijuana use while taking prescription medications, thousands of people will receive information — in English and Spanish — about possible drug interactions. Patients will be referred to drugs.com to use as a resource to check for dangerous drug interactions between THC, CBD and their own prescription medications. They will also be directed to fill out a quick survey about marijuana and drug interactions to be entered for a chance to win a $100 gift card.

“The use of marijuana can, at times, be confusing for the general public because it is legal for adults in California,” says Oh. “It is important to remember that THC can cause impairment, no matter how it is used, and marijuana can be dangerous when combined with prescribed medications. We want everyone to be aware about possible drug interactions so that they can protect themselves and their loved ones from harm.”

Talk to your pharmacist about possible drug interactions between your prescription medications and other products, food or drink items, and other medications or drugs, such as marijuana. Learn more about possible interactions at drugs.com.