Cannabis has the potential to interact with various medications by altering their metabolism and effectiveness. These interactions primarily occur through the cytochrome P450 (CYP) enzyme system, a family of liver enzymes responsible for metabolism of many drugs. Cannabis compounds, particularly tetrahydrocannabinol (THC) and cannabidiol (CBD), can inhibit or induce these enzymes, affecting drug levels in the body. Prescription medications can also have an effect on these enzymes, which are also responsible for the metabolism of cannabinoids (THC/CBD) and therefore, can increase levels and side effects from cannabis.
Taking cannabis with medications can change how well your medications work or increase your risk of side effects.
- In some cases, these reactions may be severe.
- Below is a list of medications that could possibly interact with marijuana. This is NOT a complete list. If you have questions about interactions between marijuana and your medications, talk to your doctor or provider or call the Poison and Drug Information Center at 1-800-222-1222.
- If you are a healthcare professional and want to read more about drug interactions and kinetics, please visit our Healthcare Professionals section and view the Scientific Journal Articles.
Increased Drug Levels
Cannabis use can slow down the metabolism of certain medications, leading to higher concentrations in the body and potentially increased side effects or toxicity.
Cannabis may increase the risk of bleeding when taken with blood thinners like Warfarin.
Decreased Drug Effectiveness
Cannabis may increase the metabolism of some drugs, resulting in lower therapeutic levels that reduce the drugs effectiveness.
When used with antiviral drugs, marijuana may reduce their effectiveness.
Additive Effects Can Occur
An additive effect occurs when two substances with similar effects combine to produce a stronger overall effect. Additive effects may occur when cannabis is combined with central nervous system depressants such as alcohol, opioids, or benzodiazepines.
Drugs May Increase Cannabinoid Levels
Drugs that are inhibitors of cytochrome P450 CYP3A4, can lead to increased serum levels of both THC and CBD.
Ketoconazole, macrolides, and verapamil may cause increased THC/CBD levels when used together with cannabis.
Amplified Effects from Psychiatric Medicaitons
Cannabis has shown to affect neurotransmitters like dopamine and serotonin. Theoretically this may cause altered effects while taking antipsychotic or antidepressant drugs.
Important Considerations
Due to the complex nature of drug interactions and individual variability, it is important to have a discussion with a healthcare professional before combining cannabis with prescription medications.
It is recommended to avoid mixing cannabis with alcohol or other drugs.
| Generic Name | Brand Name | Possible Interaction | Possible Outcome |
|---|---|---|---|
| Alprazolam | Xanax | Additive Effects | Additional drowsiness |
| Amitriptyline | Elavil | Increased Medication Concentration | Increased Medication Side Effects |
| Amlodipine | Norvasc | Increased Marijuana Concentration | Increased Marijuana Side Effects |
| Apixaban | Eliquis | Increased Medication Concentration | Increased Medication Side Effects |
| Aripiprazole | Abilify | Increased Medication Concentration | Increased Medication Side Effects |
| Atorvastatin | Lipitor | Increased Medication Concentration | Increased Medication Side Effects |
| Buspirone Hydrochloride | Buspar | Increased Medication Concentration | Increased Medication Side Effects |
| Carvedilol | Coreg | Increased Medication Concentration | Increased Medication Side Effects |
| Celecoxib | Celebrex | Increased Medication Concentration | Increased Medication Side Effects |
| Clonazepam | Klonopin | Increased Medication Concentration | Increased Medication Side Effects |
| Clopidogrel Bisulfate | Plavix | Increased Medication Concentration | Increased Medication Side Effects |
| Cyclobenzaprine | Amrix | Decreased Drug Concentration (Smoking Marijuana) | Drug is less effective |
| Desogestrel; Ethinyl Estradiol | Reclipsen, Desogen, Kariva (others) | Increased Medication Concentration | Increased Medication Side Effects |
| Diazepam | Valium | Increased Medication Concentration | Increased Medication Side Effects |
| Diclofenac | Increased Medication Concentration | Increased Medication Side Effects | |
| Diltiazem Hydrochloride | Cartia, Tiazac | Increased Marijuana Concentration | Increased Marijuana Side Effectss |
| Donepezil Hydrochloride | Aricept | Increased Medication Concentration | Increased Medication Side Effects |
| Doxazosin Mesylate | Cardura | Increased Medication Concentration | Increased Medication Side Effects |
| Doxycycline | Increased Marijuana Concentration | Increased Marijuana Side Effectss | |
| Drospirenone; Ethinyl Estradiol | Yaz, Ocella, (others) | Increased Medication Concentration | Increased Medication Side Effects |
| Enalapril Maleate | Vasotec | Increased Marijuana Concentration | Increased Marijuana Side Effectss |
| Escitalopram Oxalate | Lexapro | Increased Marijuana Concentration | Increased Marijuana Side Effectss |
| Estradiol | Estrace, Natazia (others) | Increased Medication Concentration | Increased Medication Side Effects |
| Ethinyl Estradiol; Norgestimate | Ortho-Cyclen, Ortho Tri-Cyclen (others) | Increased Medication Concentration | Increased Medication Side Effects |
| Fenofibrate | Fibricor, Trilipix (others) | Increased Marijuana Concentration | Increased Marijuana Side Effectss |
| Finasteride | Propecia | Increased Medication Concentration | Increased Medication Side Effects |
| Fluconazole | Diflucan | Increased Marijuana Concentration | Increased Marijuana Side Effectss |
| Fluoxetine Hydrochloride | Prozac | Increased Marijuana Concentration | Increased Marijuana Side Effectss |
| Guanfacine | Intuniv | Increased Medication Concentration | Increased Medication Side Effects |
| Hydrocodone/APAP | Vicodin | Additive Effects | Increased Drowsiness and Sedation |
| Ibuprofen | Advil, Motrin | Increased Medication Concentration | Increased Medication Side Effects |
| Ketoconazole | Increased Marijuana Concentration | Increased Marijuana Side Effectss | |
| Lamotrigine | Lamictal | Increased Marijuana Concentration | Increased Marijuana Side Effectss |
| Loratadine | Claritin | Increased Medication Concentration | Increased Medication Side Effects |
| Lorazepam | Ativan | Increased Medication Concentration | Increased Medication Side Effects |
| Losartan Potassium | Cozaar | Increased Medication Concentration | Increased Medication Side Effects |
| Methylprednisolone | Medrol | Increased Medication Concentration | Increased Medication Side Effects |
| Montelukast | Singulair | Increased Medication Concentration | Increased Medication Side Effects |
| Morphine | MS Contin | Additive Effects | Increased Drowsiness and Sedation |
| Naproxen | Aleve, Naprosyn | Increased Medication Concentration | Increased Medication Side Effects |
| Ondansetron | Zofran | Increased Medication Concentration | Increased Medication Side Effects |
| Oxybutynin | Ditropan | Increased Medication Concentration | Increased Medication Side Effects |
| Oxycodone | Oxycontin | Additive Effects | Increased Drowsiness and Sedation |
| Quetiapine Fumarate | Seroquel | Increased Medication Concentration | Increased Medication Side Effects |
| Rivaroxaban | Xarelto | Increased Medication Concentration | Increased Medication Side Effects |
| Rosuvastatin | Crestor | Increased Medication Concentration | Increased Medication Side Effects |
| Simvastatin | Zocor | Increased Medication Concentration | Increased Medication Side Effects |
| Sitagliptin Phosphate | Januvia | Increased Medication Concentration | Increased Medication Side Effects |
| Tamsulosin Hydrochloride | Flomax | Increased Medication Concentration | Increased Medication Side Effects |
| Trazodone Hydrochloride | Desyrel | Increased Medication Concentration | Increased Medication Side Effects |
| Valacyclovir | Valtrex | Increased Medication Concentration | Increased Medication Side Effects |
| Valsartan | Diovan | Increased Medication Concentration | Increased Medication Side Effects |
| Verapamil Hydrochloride | Calan, Verelan (others) | Increased Medication Concentration | Increased Medication Side Effects |
| Warfarin | Coumadin | Increased Medication Concentration | Increased Risk Of Bleeding |
*Side Effects and Drug Interactions were noted in studies that included marijuana, Dronabinol and Nabilone. Dronabinol and Nabilone are Food and Drug Administration-approved medicines derived from tetrahydrocannabinol (THC), a main component of marijuana.
*Additive Effects mean the effect of two substances used together is greater than using either substance alone