Information on dosing cannabis is what holds most doctors back from prescribing cannabis medicine.
Cannabis has a history of use as a medicine that starts far before written evidence. Europe and North America only have records for the century between 1840 and 1940, but China for thousands of years before that. Fast forward, through much anecdotal evidence and accumulating research, cannabis is once again a mainstream medicine. Patients the world over, however, have the same issue – how to ensure they are dosing cannabis properly. Sadly, there are still no consistent guidelines.
Even today’s newly minted doctors remain largely uneducated with respect to cannabis and the endocannabinoid system (ECS). In fact, a recent survey taken in the USA found that 89.5% of the recent medical school residents and fellows felt unprepared to prescribe cannabis. And only 35.3% felt ready to answer cannabis questions.
Information on Properly Dosing Cannabis is on the Way
The best resource we currently have is an article published by internist, Dr. Caroline A. MacCallum and neurologist, Dr. Ethan B. Russo, that offers a review of the literature on dosing cannabis. Their personal observations could serve as a guide to suggested Good Clinical Practice (GCP) as these apply to cannabis.
Pharmacokinetics of Cannabis
And important aspect of correctly dosing cannabis is to consider its pharmacokinetic properties. This means the absorption, distribution and metabolism of cannabinoids and terpenes within the human body. These factors will determine the onset and duration of the action at each dosage level.
Absorption has the highest incidence of change because it depends on how fat-soluble the method is and also the bioavailability dictated by the same. For example, more cannabinoids are absorbed when cannabis is taken under the tongue than when it is smoked. One final impact on absorption is the individual tissue differences in organs, such as gastric absorption or through the skin.
Best Method of Absorption for Cannabinoids
Cannabinoids are lipophilic and have low water solubility. Therefore, fat, oils, or polar solvents (ethanol) are needed for topical or oral routes. Absorption can be improved through the use of newer technology, such as nanotechnology, ionized particles, or omega fast in the carrier oil. Routes of administration include: smoking, vaporization, oral, topical, and suppositories.
Recommendations for Dosing THC
Cannabis prescriptions requiring high THC are easier to judge as the producer provides concentrations based on inhalation. Vaping is subject to more variables which can influence dose: size of the chamber, depth of the inhalation, breath holding, strength of the THC in the chemovar etc.
Ideally the patient should start using a THC-predominant preparation at bedtime to limit adverse events and encourage the development of tolerance. A good starting point is the following regimen:
- Days 1–2: 2.5 mg THC-equivalent once a day
- Days 3–4: 2.5 mg THC twice a day
- Increase as needed and as tolerated to 15 mg THC-equivalent divided BID-TID
- Doses exceeding 20–30 mg/day may increase adverse events or induce tolerance without actually improving the reduction of treated symptoms, such as pain.
What About Adverse Reactions?
In the case of adverse events, cannabis is in the safety zone. It has a superior safety profile in comparison to many other medications, with no reported deaths from overdose. This is due to the lack of the CB1 receptors in brainstem cardiorespiratory centers.
Contraindications occur during pregnancy and lactation, despite a long history of usage. Also, use of THC in children and teens remains a subject of a debate, even with some very positive results with pediatric epilepsy patients. There are some cautions also with the cardiac patients, such as angina risk.
With cannabis-based medicine returning as a mainstream player in the pharmaceutical field, it is necessary for the medical community to gain greater knowledge and understanding of the pharmacology, dosing and administration to maximize therapeutic potential and minimize the adverse events.
After Dosing: Administration
Hand in hand with dosing comes the methods of cannabis administration.
For some patients, absorption methods like patches can be a great benefit. Edibles provide perhaps the longest pain relief, but quick absorption methods like vaping or smoking can provide relief the fastest. Further, if the consumer is worried about smoking, know that vaping dry cannabis buds is free from the concerns of the EVALI crisis of late 2019; vaping dry bud also removes any concerns about combustion via smoking.