Topicals, vape pens, flowers, edibles – cannabis products can come in many forms. Each of these methods of delivery is designed to achieve certain effects in a certain timeframe. For example if a person has chronic pain one might provide a patient with an infused product to create a baseline of cannabinoids, and add a vaporized product as needed for any kind of breakthrough pain.
But how do we choose our delivery methods and more importantly why does the method of intake matter? With this guide to cannabis products, you will be able to pick an appropriate route of administration for a given malady and understand why this method is the appropriate choice.
The Concept of Bioavailability
To understand why different routes of administration cause different effects, one must understand the concept of bioavailability. Bioavailability refers to the amount of the compound available in the blood to achieve effects. Each route of administration will interact with the body differently and hence will cause a varied amount of bioavailability of the active ingredients (cannabinoids, terpenes, etc).
Different Routes of Administration (ROA) and Their Bioavailabilities:
- Topical (N/A) – This ROA involves getting the actives into contact with the dermis-meaning skin-in a localized area. This means that the cannabinoids do not actually penetrate past the skin into the blood and only hit receptors in the skin and surrounding tissues.
- Oral/Ingestion (6-10%) – The oral route of ingestion differs widely from others due to the interactions that occur with the liver. This route is also highly variable in terms of timing the effects due to the differences in the size of the consumer, their stomach content, and other factors. We’ll discuss this in further detail in the next section of this article.
- Rectal (~13.5) – This ROA involves utilizing the rectum as a means of bypassing the liver and hence unwanted conversion into other metabolites. An example of a product that utilizes this route is suppositories.
- Buccal / Sublingual (10-25%) – This ROA involves keeping the product in contact with the mucous membranes in between the cheek and the gum or the capillaries found under the tongue. This enables the active components to cross directly into the blood. This ROA also minimizes the conversion of THC into other metabolites. Examples of products that utilize this route are tinctures and lozenges.
- Inhalation (~30%) – This common ROA is the quickest delivery method and achieves results in minutes. This method is best suited for bouts of acute symptoms. Examples include joints and vape pens.
- Transdermal (80 – 100%) – This ROA causes the actives to be delivered across the skin and directly into the blood. This enables the actives to bypass the liver and minimize conversion into the other metabolites produced by the oral route. Transdermal patches are a common product that utilizes this ROA.
- Intravenous (100%) – This ROA involves directly injecting the active into the blood with a carrier. To our knowledge there aren’t any injectable cannabis products on the market yet but that is likely to change soon.
Ingestion ≠ Inhalation
An important factor when considering how different routes of administration vary, is the effects of the liver which can transform the cannabinoids into other, sometimes more potent metabolites. One such instance is the metabolism of THC. During the first pass, THC is converted into a compound called 11-OH-THC which is considerably more potent than THC itself and more readily crosses the blood-brain-barrier. This makes for a much more psychoactive and lengthier experience for the consumer. This ROA is also much less predictable due to variations between consumers in body mass, stomach contents, etc.
Dosages and Bioavailability
Since different ROA’s have different bioavailability it is important to modify the dosage accordingly. Let’s consider the following example comparing the effects of a concentrate versus an infused product:
- Example: A 100 mg dab at 70% THC (inhaled) and a 25 mg THC infused product (oral)
It’s important to acknowledge that we are comparing a rapid delivery method with that of a delayed method. Firstly, lets convert that 100 mg dab into actual dose of THC administered:
- 100 mg * 0.7 = 70 mg THC
Next using the bioavailability, calculate the actual amount of THC entering the blood:
- 70 mg THC * 0.3 = 21 mg THC absorbed
Now we have a better understanding of what we’re comparing –
21 mg of THC is instantly delivered compared to 25 mg being metabolized over a longer duration with different metabolites.
What to ask when choosing an ROA for a patient
Now that you have an idea of what the different ROAs are its important to know what questions to ask the consumer to make the right suggestions. Some questions that come to mind are:
- What are the needs of the consumer?
- How potent does the product need to be to achieve the desired effect?
- How quickly does the consumer need to feel effects?
- How long does the consumer want the effects to last?
Different ROA’s achieve different results per dosage and active chemical contents. For Cannabis products, we’ve barely scratched the surface of what types of solutions could be conceived. When you consider the vast number of available Cannabinoids, Terpenes and other active Compounds found in the plant, coupled with a perpetually increasing understanding of the Endocannabinoid System, the possibilities are virtually endless.