Cannabis (marijuana) is a drug that is made up of the leaves, flowers, and buds of the cannabis plant. Medical cannabis is cannabis prescribed for medical conditions such as cancer, AIDS, spasticity or multiple sclerosis. Medical cannabis can help treat symptoms like pain, nausea, and lack of appetite.
THC and CBD are the two main cannabinoids in the cannabis plant that are studied, though there are more than 100. THC affects how you think, act, and feel. It can make you feel "high." CBD can help you feel relaxed without the "high." And it may lessen pain and other symptoms.
There are many types, or strains, of cannabis. Each strain has a different THC-to-CBD ratio. Because of this, some strains have different effects than others. For example, if a strain of cannabis has a higher ratio of THC to CBD, it's more likely to affect your judgment, coordination, and decision making.
Medical cannabis may be helpful for some health conditions. These may include:
Cannabis is available as a dried plant, oil extract, and products you put on your skin. It can also be added to homemade foods such as baked goods or candy (edibles). They usually contain both THC and CBD. Medicine that contains THC are also available. These include:
If you think you might want to try medical cannabis, talk to your doctor about what type of cannabis might help relieve your symptoms. You can also visit the
Medical Use of Cannabis - Health Canada website for more information.
There are many ways people can use medical cannabis. More research is needed to understand the effectiveness of each of these different uses.
For example, people can:
How soon and how long you may feel the effects of cannabis depends on several things, including how it was taken. For example, when cannabis is smoked, the effects can usually be felt within seconds after inhaling. On the other hand, when cannabis is eaten, it may take several hours to feel the full effect. Since the effects aren't felt right away, people may think they need more and use too much. To avoid this, start with small amounts until you know how edibles affect you. Or follow your doctor's instructions on how much to use.
The type of cannabis you have used, how much you've used and how long you've been taking it can also affect how your body responds to it. You may feel the effects of cannabis for hours after you use it.
Cannabis can interact with many other medicines. It can be dangerous if you use it with medicines that make you sleepy or control your mood. These include sedatives, anxiety drugs, antidepressants, and opioids. It can also be dangerous to use cannabis with alcohol, tobacco, and/or other drugs.
Cannabis can affect your blood pressure, so use caution if you take medicine for this condition. It also increases the chance of bleeding if you're on blood thinners.
Before you try cannabis, talk to your healthcare provider about other medicines you use. Also talk to your healthcare provider about any personal or family history of substance use disorder or mental health disorders. Using cannabis may make these problems worse.
Cannabis may affect your judgment, memory, concentration, coordination, and decision making. Don't drive or operate machinery after using cannabis.
Cannabis can affect different people in different ways. Side effects may include:
Long-term regular use of cannabis may increase your risk for severe nausea and vomiting (cannabinoid hyperemesis syndrome, or CHS). People who have CHS may feel very thirsty and have belly pain and diarrhea. They may vomit more than 20 times a day. Bouts of vomiting may last more than 24 hours.
If you smoke cannabis, the smoke can make you cough and wheeze. It can even damage and irritate your lungs and airways. This can lead to bronchitis (an irritation of the airways that lead to your lungs).
If you are using medical cannabis and are pregnant or think you might be or are breastfeeding, talk to your healthcare provider. It can affect your baby's development.
Some people who regularly use cannabis may develop
cannabis use disorder. This can range from mild to severe (dependency). They may find it hard to control their use and keep using cannabis even though it's having harmful effects on their lives.
The risk of cannabis use disorder is higher in people who:
People who use cannabis often and then quit may have withdrawal symptoms. These include anxiety, trouble sleeping, and intense cravings for the drug.
Using cannabis isn't risk-free. But there are things you can do to reduce your risk of getting sick or injured.
Contact your healthcare provider if you have unwanted side effects or you think you have a problem with cannabis use.
Current as of: April 9, 2019
Author: Adapted with permission of Healthwise ®
This material is for information purposes only. It should not be used in place of medical advice, instruction, or treatment. If you have questions, talk with your doctor or appropriate healthcare provider. This information may be printed and distributed without permission for non-profit, education purposes. The content on this page may not be changed without consent of the author. Contact firstname.lastname@example.org.