Module 5: Dosing
Pre-defined dosages for the medicinal use of cannabis have not been established. Numerous variables such as the complex pharmacology of cannabinoids, inter-individual variability in cannabinoid receptor structure, function and distribution, genetic differences in cannabinoid metabolism, pharmacological tolerance, prior exposure to cannabinoids and various routes of administration, have all made it very difficult to develop a uniform dosing schedule.
Dosing therefore remains highly individualized and the standard recommendation is to start at a low dose and to allow the patient to slowly self-titrate to therapeutic effect. If intolerable side-effects occur, patients can stop therapy or reduce their dose.
The monograph for the synthetic THC drug; dronabinol (Marinol®) indicates that a dose as low as 2.5 mg given daily is associated with a therapeutic effect (1). Dosing ranges for the few approved cannabinoid therapies vary from 2.5 mg – 40 mg THC/day for dronabinol, from 0.2 mg – 6 mg/day for nabilone and from 1 spray (2.7 mg THC and 2.5 mg CBD) to 16 sprays (43.2 mg THC to 40 mg CBD) per day for nabiximols (1-4).
- Abbott Products Inc. Marinol Product Monograph. 2010.
- Valeant Canada. Cesamet Product Monograph. 2009.
- GW Pharmaceuticals. Sativex Product Monograph. 2010.
- Portenoy, R. K., Ganae-Motan, E. D., Allende, S., Yanagihara, R. and others. (2012). Nabiximols for opioid-treated cancer patients with poorly-controlled chronic pain: a randomized, placebo-controlled, graded-dose trial. J.Pain. 13: 438-449.