Drug Interactions with Medical Cannabis

Medical cannabis is metabolized primarily by the hepatic cytochrome P-450 isozymes 3A4, 2C19 and 2C9 and therefore has the potential for drug interactions via CYP450 inhibition.  Make sure you check with your physician to see if there are any drug interactions you should be concerned about.

Possible drug interactions include, but are not limited to:

  • Alcohol and benzodiazepines: Cannabis use might increase the effects of alcohol and benzodiazepines. There is an increase of sedation and central nervous system (CNS) depression.
  • Anticoagulants and anti-platelet drugs, herbs and supplements:  These types of drugs, herbs and supplements reduce blood clotting. Cannabis might change how the body processes them, possibly increasing the risk of bleeding.
  • CNS depressants:  Cannabis use in combination with CNS depressants might cause an additive sedative effect.
  • Cannabinoid-opioid interactions: There is synergistic analgesia with greater-than-additive effects. There is not enhancement of cardiorespiratory suppression with combination treatment due to the very low density of cannabinoid receptors in brainstem cardiorespiratory centers. There are minimal pharmacokinetic interactions in humans with morphine, and none with oxycodone. Adding low dose cannabinoids to opioids widens the therapeutic window and should help reduce the need for opioid dose-escalation.
  • Anticholinergic Drugs: These may increase the psychoactive side effects of medical cannabis.
  • Non-Steroidal Anti-Inflammatory Drugs (NSAIDs):  NSAIDs, in particular indomethacin, can antagonize the effects of medical cannabis.
  • Protease inhibitors: Cannabis use with use of these antiviral drugs might reduce their effectiveness.
  • Selective serotonin re-uptake inhibitors (SSRIs): Mixing cannabis with this type of antidepressant might increase the risk of mania.

If you live in a place with a medical cannabis program please have an honest conversation with your Physician to see if medical cannabis is a good fit for you. If you live in Missouri and you don’t have a Primary Care Physician, you can come see my wife, Dr. Strong in St. Louis. Dr. Strong will be providing Medical Marijuana Physician Certificates starting in June 2019.










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