The term “medical cannabis” is used to describe products derived from the whole cannabis plant or its extracts containing a variety of active cannabinoids and terpenes, which patients take for medical reasons, after interacting with and obtaining authorization from their health care practitioner.
The chemical ingredients of cannabis are called cannabinoids. The 2 main therapeutic ones are:
A Tetrahydrocannabinol (THC) is a partial agonist of CB1 and CB2 receptors. It is psychoactive and produces the euphoric effect.
B Cannabidiol (CBD) has a weak affinity for CB1 and CB2 receptors and appears to exert its activity by enhancing the positive effects of the body’s endogenous cannabinoids
3. Why do patients take it?
Medical cannabis may be used to alleviate symptoms for a variety of conditions. It has most commonly been used in neuropathic pain and other chronic pain conditions. There is limited, but developing, clinical evidence surrounding its safety and efficacy, and it does not currently have an approved Health Canada indication.
Cannabis can be smoked, vaporized, taken orally, sublingually, topically or rectally. Different routes of administration will result in different pharmacokinetic and pharmacodynamic properties of the drug.
Yes, abrupt discontinuation after long-term use may result in withdrawal symptoms. Additionally, chronic use may result in psychological dependence.
Patients taking cannabis for medical reasons generally use cannabinoids to alleviate symptoms while minimizing intoxication, whereas recreational users may be taking cannabis for euphoric effects. Medical cannabis is authorized by a prescriber who provides a medical document allowing individuals to obtain cannabis from a licensed producer or apply to Health Canada to grow their own, whereas recreational cannabis is currently obtained through illicit means.
Pharmacological cannabinoids such as Sativex (delta-9-tetrahydrocannabinol-cannabidiol) and Cesamet (nabilone) have been approved for specific indications by Health Canada, however, herbal medical cannabis has not gone through Health Canada’s drug review and approval process, nor does it have a Drug Identification Number (DIN) or Natural Product Number (NPN).
Some insurance plans may cover medical cannabis. Check each patient’s individual plan for more details.
Even though pharmacists are not dispensing medical cannabis at this time, it is important for them to understand how their patients may use and access medical cannabis in order to provide effective medication management. Pharmacists may provide counselling on areas such as contraindications, drug interactions, management of side effects, alternative therapies, potential addictive behaviour and appropriate use.
You can find more information on Health Canada’s website:” https://www.canada.ca/en/health-canada/services/drugs-health-products/medical-use-marijuana/medical-use-marijuana.html