Bioavailability is a pharmacological term referring to the degree and rate at which an administered drug is absorbed by the body's circulatory system. It is used to determine the correct dosage of any medication administered non-intravenously (not directly into the bloodstream). This includes pills, patches, tinctures, suppositories, inhalable products and edible products. Some of the things that can affect bioavailability include a person’s metabolic rate, sleep cycles, drug and food interactions, health of the gastrointestinal tract, age, and the formulation of the product itself.
Sublingual cannabis products like tinctures, dissolvable pills and drinks provide a more efficient means of absorption because they can bypass the whole digestive tract and enter directly into the bloodstream via the highly permeable oral cavity. Sublingual products may be absorbed almost instantly. Different areas of the mouth have varying levels of permeability (under the tongue being the most porous followed by the cheek then the roof of the mouth) which means that cannabinoids coming into contact with these different areas will have different rates of absorption. For this reason, sublingual cannabis products should be administered under the tongue for the quickest results (sometimes as little as a few minutes) but should still work if they accidentally get swallowed – the patient will just have to wait for them to be digested first.
When cannabinoids are absorbed sublingually, the effects of edibles are not only felt quicker but have an increased bioavailability of around 50 – 75% in some cases. This means that less product is needed to feel its effects, which saves both time and money. Not only that, but sublingual dosages are easier to manage because fewer variables are at play – no digestion or “helper foods” are needed to be effective -- and because it works so quickly, there is less likelihood of an uncomfortable case of overconsumption.
Oral administration is a fancy way to say “eating”. Unlike inhaled cannabis, edible cannabis is metabolized by the liver. This means that more THC is converted into usable forms by the body, but it takes longer than sublingual absorption (usually 30-90 minutes.) When you orally consume cannabis, the body produces more of a certain metabolite called 11-hydroxy-THC. This THC metabolite is four to five times more psychoactive than THC. It also can cross the blood-brain barrier more easily. This means that a patient may feel more effects from an orally administered form of cannabis than other forms.
Some forms of cannabis that can be absorbed orally are also able to be absorbed sublingually. It is up to the patient how they want to consume these versatile products. It should be noted that sublingually absorbed products wear off sooner than orally consumed products, which also take longer to kick in.
Inhalation based administration can be broken into two categories: vaporization and nebulization. Inhalation of any kind is one of the fastest absorption methods for patients, taking less than a minute for the compounds to be absorbed. Vaporization is a phase transition from the liquid phase to vapor. Once the cannabis oil is in vapor form, it is able to be absorbed by the tissue in the lungs. It is important to vaporize at low temperatures so that terpenes can be utilized, and irritation can be avoided. Nebulization delivers the oil in the form of a mist that can be inhaled into the lungs. Nebulizers are commonly used for the treatment of respiratory issues, and would most likely come to market in the form of an inhaler.
Topical administration can be broken into two categories. Skin-deep topicals such as salves and lotions are meant for local application. This means that the lotion or salve is being applied to the location on the body that needs to be treated. These topicals are only permeating the top layers of the skin, but may be helpful for neuropathies, pain and other issues.
Other topicals, such as transdermal patches and gels, can permeate at least twelve layers of skin, allowing them to enter the bloodstream and truly be absorbed by the body. Transdermal patches have the ability to deliver cannabinoids to your system at a controlled release-rate.
Some patients are already comfortable with self-administration and dosing, but others may have never consumed before. It is important to follow the “L.E.S.S.” method for patients who are new to cannabis.
L.E.S.S. = LOW, ESTABLISHED, SLOW, SUPPLEMENTED
LOW = Starting with a small dose. 1mg is a very small dose for most people and is a conservative starting point for young children or adults who are nervous about the effects of cannabis. 5mg is a small, but potentially significant dose that may be a good starting point for people who are new to cannabis.
ESTABLISHED = Establishing the effect that a certain dose has on a patient will help them to decide whether to up or down dose for future administration.
SLOW = It is important to have patience and remember that cannabis is sometimes absorbed slowly (depending on the method of administration.) The peak effects may not be felt until after 90 minutes for some people who are consuming orally.
SUPPLEMENTED = A low oral dose makes a good base. Once the effects are felt and have evened out, additional cannabis can be added to increase effects as desired. It makes it practical to "underdose" with oral cannabis without having the experience be disappointing.