Does Weed Interact With Any Medications? Here’s The Truth

Everything you need to know about mixing THC with medications.

Cannabis is renowned for being a safe drug. With no recorded deaths or potentially fatal overdoses, it seems as though we can use cannabis whenever and however we want.

However, that’s not the case for everyone. Have you ever wondered if your cannabis use is lessening the efficacy of certain medications? Could it possibly interact with prescription medications in a negative way? What if cannabis is actually increasing the effects of your medications?

We delved into the science and spoke with a doctor to find out if there are any cannabis-drug interactions you should be worried about. Below, we’ve included an in-depth rundown of the relationship between various medications and cannabis.

Before using weed with your prescription medications, it’s always recommended to speak with your doctor or healthcare provider for a more precise answer for your specific situation. Until then, here’s what to expect and what to avoid when mixing certain medications with cannabis. Read on to learn more.

Does Cannabis Interact With Medications?

The short answer is yes. The active compounds in cannabis, like THC and CBD, do have the potential to interact with prescription meds in a variety of ways. How? It begins in the liver with a group of enzymes known as the cytochrome P450 system.

The cytochrome P450 system metabolizes about 60 percent of the world’s pharmaceutical drugs. But they also break down cannabinoids like CBD and THC. The issue arises when two different drugs are “fighting” for the same enzyme pathways.

Cannabinoids could potentially “hog” those enzymes, inhibiting the effectiveness of prescription drugs that use the same pathways.

Interestingly, Jordan Tishler, MD and President of InhaleMD, a group of medical cannabis physicians in Massachusetts, tells Herb that some of these enzymes are really busy while others are not.

“The enzyme that breaks down CBD is one of the busy ones, whereas the one that handles THC is less so.” Basically, CBD is much more likely to interfere with your prescription meds than THC. But that’s not to say that THC won’t interfere as well.

There are thousands of medications out there, so knowing if your specific prescription could potentially be hindered by cannabis use and THC is essential. As mentioned, always speak with your doctor before using weed and medications. They will provide a more specific answer for your unique situation.

Because we’ve already written an in-depth explainer of CBD drug interactions which you can read here, for the rest of this piece, we’ll focus on THC’s potential to interact with other drugs.

How Weed Can Interact With Some Medications

While there aren’t any lethal combinations of mixing high-THC cannabis with prescription meds, there are some potential drug interactions that you should be aware of.

Michael Verbora, MD, and member of “Doctors for Responsible Access,” explains in an article for physicians that mixing cannabis with sedating drugs such as benzodiazepines, like Klonopin or sleeping pills, could increase the pills’ sedating effects.

He warns that this could increase the risk of car accidents or falls, so it’s important to tread lightly when mixing cannabis and these medications.

A good rule of thumb is to “start low and go slow” to monitor how your body reacts to the mix.

Another area of interest is the combination of opioids and cannabis. While cannabis could increase the sedative effects of opioids, this could actually be a good thing for those trying to reduce their opioid use.

Because cannabis also helps people with pain management, inflammation, and sleep, it has the potential to help those treating pain with opioids, allowing them to lower their opioid intake while still managing their particular conditions.

A 2011 study found that combining cannabis and opioids was increasing people’s pain relief while simultaneously reducing their opioid usage, a win-win for health and public safety. Still, there are things to consider when taking cannabis with opioids.

Below, we’ve included a brief rundown of how cannabis interacts with the most common medications.

Antibiotics: Fortunately, cannabis hasn’t been noted to have negative interactions with antibiotics. In fact, the plant has antibacterial properties as well, so using them together isn’t only safe but may be beneficial.

Pain Medications: Painkillers like codeine, Percocet, and Vicodin may have dangerous effects when mixed with cannabis. They suppress the central nervous system and can cause severe blood pressure drops, cognitive issues, lack of coordination, and brain fog.

Opioids: Although the study above noted that combining cannabis and opioids could increase relief, it could also suppress the central nervous system and lead to unwanted side effects like lethargy, extreme exhaustion, and even coma.

Psychiatric Medications: Psych meds like antidepressants and Zoloft, and Prozac don’t have many negative effects when mixed with cannabis. Although, weed and SSRIs increase serotonin, which can lead to serotonin syndrome (a toxic influx of serotonin in the brain).

Blood Thinners: No evidence suggests that cannabis and blood thinners shouldn’t be used together. However, stay on the lookout for signs that your blood might be too thin, like bleeding gums, nose bleeds, random bruising, excessive bleeding, heavy menstrual bleeding, and blood in urine/feces.

Sedatives: Cannabis and sedative medications like Ambien and Benadryl amplify the effects of one another. It’s not necessarily good, as it could increase the risk of severe exhaustion, lethargy, lack of coordination, dizziness, and memory loss.

THC Interactions: Increasing And Decreasing The Bioavailability Of THC

When you combine cannabis with some prescription medications, it can increase or decrease the bioavailability of THC.

This means some meds could interact with your weed to make you feel more or less high. Verbora explains that some drugs decrease or increase how THC is metabolized in the body. Therefore, certain drugs can increase or decrease weed’s effects.

Verbora writes that the drugs that could potentially increase THC’s effects include:

•     Antidepressants like Fluoxetine
•     Proton Pump Inhibitors like Cimetidine
•     Macrolides like Clarithromycin
•     Antimycotics
•     Calcium Antagonists
•     HIV Protease Inhibitors
•     Amiodarone
•     Isoniazid

He also lists some drugs that could potentially decrease THC’s effects. This could be a problem if you are using cannabis to alleviate symptoms. You may want to up your dose of cannabis if you’re not getting relief and also take one of the following medications or supplements:

•     Phenobarbital
•     Rifabutin
•     Primidone
•     Saint John’s Wort

Does Consumption Mode Matter For Cannabis Drug Interactions?

Does it affect potential drug interactions if you smoke, vape, or eat edibles to consume your cannabis? Tishler says no. “The manner of ingestion is not relevant assuming that that manner is effective itself,” he tells Herb.

However, what could affect cannabis drug interactions is the dose of THC or CBD you consume. Higher doses have a larger potential to have an effect, especially if your meds are metabolized by the cytochrome P450 system.

While the consumption method doesn’t matter per se when it comes to dose, many edibles and tinctures, like cannabis oils, are stronger than hitting a vape pen or a joint and, therefore, could have a potentially more potent effect.

If you’re still wondering if your prescription medication could interact with cannabis and THC, there are some resources you can use. Of course, we always encourage you to talk to your doctor or find one who’s open to exploring medical cannabis options.

A Quick Tip From Herb: If your meds warn against mixing with grapefruit, then there’s a chance they’ll also interact with cannabis.

Another thing you can do is check out this interactive tool on drugs.com. It lists over 600 potential interactions between cannabis and other medications to help you figure out if your combination will have any effect.

While cannabis drug interactions are possible, as long as you’re proactive and honest with your doctor, you should still be able to find doses of both that work for you.