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Blog by Dr. Jagmeet Sethi MD

  • Writer's pictureSethi Cannabis Clinic

When Not to Take Cannabis by Dr. Jagmeet Sethi MD

Updated: 1 day ago

Medical Cannabis has many pros and cons for CBD oil for pain, anxiety and sleep. Medical cannabis also has THC, CBG, CBN oils, different cannabis strains and various methods of consumption. However, this blog is when not to take cannabis. Medical conditions, prescription medications, and mental health conditions determine when medical cannabis is not recommended. Dr. Jagmeet Sethi, MD, from Sethi Cannabis Clinic, discusses when medical cannabis harms or side effects may be greater than the benefits.

There are more than 60+ videos on medical cannabis basics and how it helps medical conditions posted on; click here for our YouTube channel: @sethicannabisclinic

The YouTube video below by Dr. Sethi will have more detail on this topic:

Click below to view the video: When Not to Take Cannabis

When not to take cannabis? See brief summary below.

If you are acutely sick with any illness requiring hospitalization, for example, you had an infection, blood clots or any other condition that required you to be hospitalized. Cannabis needs to be withheld for a minimum of 3 months or longer till things stabilize. Cannabis treatment may interfere with other medical treatments, prescription medications or mask symptoms that your doctor needs to know to treat you.

If you have had an MI (heart attack), CHF (heart failure), arrhythmia (rapid heartbeat or heart rhythm issues) or any cardiac conditions requiring hospitalization like angioplasty, cardiac bypass operation etc. In these circumstances, cannabis should not be taken for a minimum of 3 months or longer. This includes CBD oil, not just THC products. Some patients think it's safe to take CBD in these circumstances, but there are risks with CBD as well. Cannabis can mask cardiac symptoms since it helps with pain, and this can interfere with treatment. Cannabis may interact with some prescription medications like blood thinners.

However, for chronic cardiac conditions heart issues more than a year ago, and the cardiac status is stable. Cannabis can be taken but only with supervison with a medical doctor that is experienced in medical cannabis.

If you have any mental health condition that requires hospitalization or ER visits for depression, anxiety, psychosis, etc. Another reason why not to take cannabis is that it can interact with prescription medications and alter mood, making things worse. So anxiety or depression can be worse if incorrect strains or dosing. But more importantly, it interferes with medical treatment with medications since side effects and benefits are difficult to assess if cannabis is in the mix.

For chronic mental health conditions, cannabis can help, but it needs to be taken only under the supervision of a physician with experience in marijuana medicine. The cannabis doctor can help navigate which cannabis strains are best and how to manage prescription meds for their mental health condition with medical marijuana.

Don't take cannabis with mental health conditions like schizophrenia, severe depression, panic attacks, anxiety under poor control, bipolar disorder (exceptions apply if managed by a doctor), or a history of psychosis.

Why not to take cannabis if you are under the age of 25 years old. There is a large volume of data and research on the harms of cannabis in this age group, which may worsen mental health conditions and greater risks of overuse of cannabis. Patients over age of 80 years old need to be careful about when not to take cannabis. Although CBD is usually suggested, it may also not be recommended in some cases. This needs careful supervision by a cannabis doctor. For more information on this topic, please click here to watch the YouTube video:

Cannabis should not be given to patients with dementia or anyone who cannot make their own medical decisions due to their medical condition. In some circumstances, medical cannabis can be prescribed by a cannabis doctor, but mainly, these are CBD oils. Even CBD oils have risks in these patients, interact with other prescription medications and require a doctor's supervision.

Cannabis, for obvious reasons, should not be taken if there is alcohol addiction or any other substance abuse disorder or history of cannabis use disorder. Remember, cannabis interacts with alcohol since it is also metabolized in the liver.

Cannabis is not taken if there is a history of cannabis hyperemesis syndrome, a rare disorder that manifests as vomiting, mainly in patients who overuse cannabis.

People who are sensitive to prescription medication, meaning they get side effects not commonly seen. These patients also have side effects from cannabis, even CBD oil. They need careful assessment by an experienced cannabis doctor.

Interaction risks with some medications can occur. How to manage prescription medications with cannabis is a complex topic and needs a doctor's supervision. Patients on sleep or anxiety/depression meds and polypharmacy (multiple medications) are at greater risks for side effects with cannabis if not managed properly

There may be other reasons not to take cannabis since medical assessment for cannabis depends on various factors and is individual to the patient.

I hope this helps answer one of the most common frequently asked questions: When not to take cannabis?

Dr. Jagmeet Sethi, MD

Sethi Cannabis Clinic

Burlington, Ontario, Canada


Ph: (905) 681-7676

Click the button below to request an appointment with Dr. Jagmeet Sethi, MD, at Sethi Cannabis Clinic. We offer assessment for medical cannabis via virtual video appointments anywhere in Ontario or in person in Burlington, Ontario.

Medical Cannabis Videos by Dr. Jagmeet Sethi videos/podcast is a series of educational videos/podcasts. These videos/podcasts are for general information purposes only. They are not meant to diagnose and treat medical conditions and do not substitute care provided by your doctor or other health care professionals. These videos/podcasts by Dr. Jagmeet Sethi are not meant for a doctor-patient relationship. No doctor-patient relationship is formed. Please see your doctor for any medical conditions. Using this information and links from these videos is at the user's own risk. Cannabis does not help everyone, there is individual variability in risks and benefits. Cannabis use is recommended in people aged 25 years or older. If this is a medical emergency, please seek your doctor or nearest emergency room or call emergency services at 911.

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