Weed Interacts With Medications

Marijuana is the most used recreational drug in the United States. And now, medical marijuana is on the rise. Since 2013, use has more than doubled. Today, roughly 8.3 million people turn to medical marijuana to relieve anxiety, depression, insomnia and pain.

Still, we know little about how it interacts with prescription medications like blood thinners or seizure medication. But as researchers investigate cannabidiol (CBD), cannabinol (CBN) and tetrahydrocannabinol (THC) — the chemicals found in marijuana — we learn more about how weed may change how medications work in harmful ways.

Key Takeaways: Marijuana And Medication

• The chemicals in marijuana metabolize with the same proteins as most prescription medications.
• Marijuana can make some medications, like the blood thinner warfarin, too strong. It can make other medications, like tamoxifen, a breast cancer drug, too weak.
• Inhaling marijuana smoke introduces chemicals to your bloodstream faster and potentially triggers stronger interactions.

How Do The Chemicals In Marijuana Interfere With Prescription Medications?

Your body uses two families of enzymes (proteins) to metabolize CBD, CBN and THC. Those same enzymes also process more than 70 percent of the most prescribed medications. These frequently used drugs include:

• Acetaminophen
• Anti-anxiety and antidepressant medication
• Cholesterol medications
• Ibuprofen
• Tamoxifen
• Warfarin

Depending on how much marijuana you use and when you do it, CBD can speed up or slow down the enzymes. As a result, there’s a risk that any medication you take could become too strong or too weak. CBD also affects how quickly your body breaks down other medicines. That means your medication could build up in your body and cause more significant side effects.

According to a study in Drug Metabolism and Disposition, your body breaks down THC and CBD within 30 minutes. But that process produces other chemicals that can linger in your body for up to two weeks. Those chemicals continue to interfere with how your liver and kidneys process and clear medications from your body.

Which Interactions Are Considered High Risk?

Marijuana interacts with every drug differently. The most high-risk interactions happen with medications that have narrow therapeutic windows. A small dose change can lead to a big difference in how your body responds.

Some of the medications include:

• Benzodiazepines or opioids: When combined with marijuana, these pain relievers can increase sedation, particularly in older adults.
• Clobazam: CBD may increase the sedation effect with this seizure medication and make you sleepy or lethargic.
• Tamoxifen: Marijuana slows the body’s metabolism of this breast cancer drug. This decreases its strength and impact for people with breast cancer.
• Warfarin: Marijuana can cause this blood-thinning medication to build up in your body. As a result, you may have an increased risk of internal bleeding and death.

If you’re concerned about how pot may impact your prescription medications, talk with your doctor.

Who Is Most At Risk For Marijuana-Medication Interactions?

Anyone who uses marijuana while taking a prescription medication can experience negative interactions. But you’re at higher risk if you:

• Are over age 65
• Have liver disease or impaired liver function
• Require multiple prescription medications
• Take medications that require specific doses (anti-seizure medication, blood thinners or chemotherapy)
• Use marijuana daily or in high doses

Does The Form Of Marijuana Matter?

Yes. The way you use marijuana makes a difference in how quickly it can interact with your prescription medication.

Inhaling marijuana smoke, either by smoking or vaping, is the fastest way to get marijuana chemicals into your bloodstream. The high concentration can trigger the strongest effects. On the other hand, the marijuana in edibles takes longer to absorb. As a result, the concentration in your body is lower and less likely to produce a significant interaction.

Is It Ever Safe To Use Marijuana With Another Medication?

If your care team knows you use marijuana, they can make changes to your medication dose. They may want to monitor you more closely and offer guidance for safe use.

After you talk with your doctor, you may be able to use marijuana to:

• Combat nausea from chemotherapy
• Improve sleep
• Reduce seizures (with clobazam)

Marijuana is a natural substance. But that doesn’t mean pot is safe to use alongside every medication. The key is to protect your health and let your doctor and care team know if you use marijuana. Together, you can manage your medications and avoid unwanted interactions.

Learn More About Marijuana And Your Health

• Marijuana Bad For Health
• Safety Of Marijuana In Pregnancy
• Substance Use In Seniors
• Smoking Tobacco Or Marijuana And Your Surgery
• Marijuana & THC In Workplace