Prescription Medication and Cannabis

Liz Filmer
17 Dec 2021

Medical cannabis is becoming increasingly popular. But researchers still know relatively little about how cannabis may interact with various pharmaceutical medications. Here are a few common prescription medications that you should avoid mixing with weed.

Drug interactions are pretty complicated. Two substances might interact with each other, but they may also interact with whatever anomalies you may have going on with your biochemistry.

The following information is not exhaustive and is for educational purposes only. It would be best to always speak to a medical professional when testing out new drug interactions.


Those with heart conditions should be highly cautious with cannabis. Cannabis can cause fluctuating blood pressure levels and heart rate, making some more sensitive to a heart attack. This is especially true for novice consumers. In regulars, cannabis may slow heart rate.

Those taking beta-blockers or other blood pressure medications should be particularly cautious, as both substances can have opposite effects on heart rate. Beta-blockers lower blood pressure but slow heart rate. In regular users, cannabis may amplify the effects of beta-blockers by having an additive effect on slowing heartbeat. Either way, it's a tricky mix.


Benzodiazepines are potent sedatives in their own right. While many people mix benzos with cannabis, it can induce an uncomfortable experience. Common benzodiazepines include: Ativan, Klonopin and Xanax.

Cannabis and benzodiazepine medications can cause soothing effects on the brain, putting patients at risk of oversedation. In general, you should also avoid mixing cannabis with other sedative medications like sleeping pills.


Some evidence suggests that cannabinoids may increase the effect of some SSRIs, like Prozac. Those suffering from or at risk of manic depression (bipolar disorder) should be mindful of potential mood alterations when mixing these two types of medications.

Both cannabis and SSRIs also increase serotonin. There is a potential risk of developing sudden serotonin syndrome when combining these two drugs. Still, firm research on the subject is needed. Some common SSRIs include Prozac, Lexapro, Zoloft.


Those taking SNRI's, another class of antidepressant drugs, should be mindful of their weed consumption. Both SNRI's and cannabis can cause serotonin fluctuations. This can increase your chances of developing sudden serotonin syndrome or other undesirable mood fluctuations. Further still, some cannabis compounds may raise blood concentrations of antidepressants. SNRI's can also be used to treat nerve pain. Some common SNRIs include Effexor, Cymbalta, Pristiq.

Antipsychotic medications

Antipsychotic medications are tranquillizers. High-THC cannabis can also be sedating, which increases the possibility of interactions between the two substances when consumed together.

There is limited evidence to indicate that cannabis may heighten the effect of certain antipsychotic drugs, like Seroquel and Abilify. The significance of which is unknown. Some common antipsychotic medications include Abilify, Clozaril and Seroquel.

If you are not sure whether your medication may react badly with cannabis, check with your doctor, pharmacist, or you use one of the "med checker" services found online.


Liz Filmer