Administering Medical Marijuana

Please review Precautions/ Warnings before considering the use of medical marijuana.

Treatment decisions regarding the medical use of marijuana are best made together between patients and their health care practitioners.

Dosing and Administration of Medical Marijuana

What is the daily dose of marijuana (cannabis) that patients currently use?

How much marijuana and THC is in a typical joint or used in a vaporizer?

Dosing and Administration of Medical Marijuana

Below are summary comments on dosing and routes of administration of medical marijuana along with references to the published literature from which they are derived.  Healthcare practitioners who may authorize the medical use of marijuana are encouraged to review more detailed information on dosing and administration and can receive this detailed information by submitting a request, Click here.

Traditionally medical marijuana was administered by being cooked into foods and drinks or smoked using a pipe or water pipe, or rolled into a cigarette, (joint).  More recently vaporizers have offered an option to deliver the cannabinoids via inhalation (vaping) without having to incinerate the plant material.  These different routes of administration are associated with different rates of absorption of the active ingredients and also differ in the total amount of active ingredient absorbed from the plant material.  Additionally individual patients differ genetically in the structure and function of cannabinoid receptors and how they metabolize cannabinoids.  This also affects bioavailability.  Prior exposure to cannabis and tolerance to cannabinoids are also clinically significant.  Add to this the variable potency of the strains of cannabis that are available to patients and one can appreciate the difficulty in establishing precise dosing schedules for cannabis. However, less precise, more individualized dosing guidelines for smoked and inhaled cannabis have been published.

Carter, G. T., Weydt, P., Kyashna-Tocha, M., and Abrams, D. I. (2004). Medicinal cannabis: rational guidelines for dosing. IDrugs. 7: 464-470.  The authors state “dosing is highly individualized, so a patient-determined, self-titrated dosing model is recommended”.

Health Canada. Information for Health Care Professionals - Cannabis (marihuana, marijuana) and the cannabinoids; February 2013 (available on the Health Canada website). “Dosing remains highly individualized and relies to a great extent on titration. Patients with no prior experience with cannabis and initiating cannabis therapy for the first time are cautioned to begin at a very low dose and to stop therapy if unacceptable or undesirable side effects occur. Consumption of smoked/inhaled or oral cannabis should proceed slowly, waiting between puffs for a few minutes and waiting 30 - 60 min between bites of cannabis-based oral products (e.g. cookies, baked goods) to gauge for strength of effects or for possible overdosing.”

College of Family Physicians of Canada. Authorizing Dried Cannabis for Chronic Pain or Anxiety: Preliminary Guidance from the College of Family Physicians of Canada. Mississauga, ON: College of Family Physicians of Canada; 2014.  This document available on the College’s website http://www.cfpc.caand contains a recommendation on Dosing.

What is the daily dose of marijuana (cannabis) that patients currently use?

The medical cannabis program of the Netherlands published tracking data on over 5,000 patients using marijuana for medical purposes from 2003-2010.  The study reported the average dose of dried marijuana used was 0.68 grams per day.  The marijuana used had varying percentage of THC and other cannabinoids. Hazekamp, A., and E.R. Heerdink (2013). The prevalence and incidence of medicinal cannabis on prescription in The Netherlands. Eur. J. Clin. Pharmacol. Published online April 16, 2013.

According to the 3 published articles below, the majority of people using marijuana for medical purposes (either smoked or orally ingested) reported using between approximately 1 - 3 g of cannabis per day or 10 - 20 g per week.  

Clark, A. J., Ware, M. A., Yazer, E., Murray, T. J. and others. (2004). Patterns of cannabis use among patients with multiple sclerosis. Neurology. 62: 2098-2100.

Carter, G. T., Weydt, P., Kyashna-Tocha, M., and Abrams, D. I. (2004). Medicinal cannabis: rational guidelines for dosing. IDrugs. 7: 464-470.

Ware, M. A., Adams, H., and Guy, G. W. (2005). The medicinal use of cannabis in the UK: results of a nationwide survey. Int.J.Clin.Pract. 59: 291-295.

How much marijuana and THC is in a typical joint or used in a vaporizer?

The World Health Organization (WHO) suggests that a typical marijuana cigarette (joint) contains between 0.5 and 1.0 gram of cannabis (average 0.75 grams).  Commercially available strains of cannabis can contain up to 30% THC.  An average joint of a 10% THC cannabis strain would contain 75mg of THC  (0.75 grams X 10% THC content).

Using vaporizers, typically between 50mg and 500mg of dried marijuana is used at one time.  Using a 10% THC strain would mean that between 5mg and 50mg of THC would be contained in this dose. See also Use of Vaporizers to Administer Medical Marijuana.

It is important to remember that in addition to differences in the amount of cannabis used with the different routes of administration (smoking, vaporizing / vaping, oral ingestion), each route of administration is different with respect to the percentage of THC/ other cannabinoids that it delivers to the system and the timing of that delivery.

Healthcare practitioners are encouraged to review more detailed information on dosing and administration and can receive this information by submitting a request, Click here.