Medical cannabis comes in a wide variety of strains, from both cannabis sativa and cannabis indica plants and in combinations of those two. It is believed that THC and CBD are associated with the treatment and management of different conditions and illnesses. An incredibly complex interaction occurs between the two active components and the 700 other metabolites in the whole bud. One conclusion that has been drawn from research is that CBD, as a non-psychoactive component of cannabis tempers and reduces the psychoactive effect of THC .
THC is associated with the management of :
- Lack of appetite
- Nausea and vomiting
- Movement disorders
CBD is associated with the management of:
- Movement disorders
Potential Side Effects of Medical Cannabis
According to Health Canada, potential risks ‘[…] may vary depending on the amount cannabis used and the concentration of cannabinoids in the cannabis product, the frequency of cannabis use, the patient’s age and medical condition, previous experience with cannabis or cannabinoids, and the use of other prescription and non-prescription drugs:.
Most common side effects
- Dizziness, dry mouth & drowsiness
- May reduce the ability to react and can cause a lower concentration
- Euphoria/”high”, blurred vision, postural hypotension, red eyes & headache
- Anxiety, depression, ataxia, asthenia, cognitive effects & tachycardia , 
For more on potential side effects visit the Health Canada serious warnings and precautions page.
Cannabis and Driving
According to the College of Family Physicians of Canada (CFPC), Patients taking dried cannabis should be advised not to drive for at least (1):
- 4 hours after inhalation
- 6 hours after oral ingestion
- 8 hours after inhalation or oral ingestion if the patient experiences euphoria 
Who should not take medical cannabis?
According to Health Canada, medical cannabis should not be used if you:
- are under the age of 18
- are allergic to any cannabinoid or to smoke
- have serious liver, kidney, heart or lung disease
- have a personal or family history of serious mental disorders such as schizophrenia, psychosis, depression or bipolar disorder
- are pregnant, are planning to get pregnant, or are breast-feeding
- are a man who wishes to start a family
- have a history of alcohol or drug abuse or substance dependence
For more detailed information on potential therapeutic uses and risks associated, please consult Health Canada’s ‘Consumer Information: Cannabis (Marihuana, marijuana)’ or for more detailed information: ‘Information for Health Care Professionals: Cannabis (marihuana, marijuana) and the Cannabinoids’.
More information on the benefits and effects of medical cannabis
Potency of marijuana – Information from the University of Washington’s Alcohol & Drug Abuse Institute on the potency of marijuana, the strains available and how the plant is prepared and used
Medical cannabis: The Entourage Effect – The interaction of various compounds in cannabis is known as the ‘entourage effect’. This link explains how it works.
Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects – A special issue covering cannabinoids in biology and medicine from the British Journal of Pharmacology
Dried cannabis prelim guidance – A guidance document from the College of Family Physicians in Canada (CFPC) entitled ‘Authorizing dried cannabis for chronic pain or anxiety: preliminary guidance’.
 ‘The Cannabinoid Spectrum.’ – American Herbal Pharmacopoeia’, http://www.stcm.ch/files/us-herbal-pharmacopoeia_cannabis-monography.pdf
 CONSUMER INFORMATION Cannabis (Marihuana, Marijuana). Ottawa: Health Canada, 2013. http://www.hc-sc.gc.ca/dhp-mps/marihuana/info/cons-eng.php
 Authorized Dried Cannabis For Chronic Pain And Anxiety.’ College of Family Physicians of Canada, Sept. 2014. Web. 21 Oct. 2014.
Br J Clin Pharmacol. 2011 Nov;72(5):735-44. doi: 10.1111/j.1365-2125.2011.03970.x. Cannabinoids for treatment of chronic non-cancer pain; a systematic review of randomized trials. Lynch ME1, Campbell F.
Clinical Journal of Pain: February 2013 – Volume 29 – Issue 2 – p 162–171 doi: 10.1097/AJP.0b013e31824c5e4c http://journals.lww.com/clinicalpain/Abstract/2013/02000/Cannabinergic_Pain_Medicine__A_Concise_Clinical.11.aspx