An Editorial by Dr. Raquel Peyraube
An important issue surrounding cannabis-based treatments is how they are administered. Routes of administration depend on several factors that are identified in each case. In order to understand the utility and indication of each of them, I will review the most common routes of administration below.
Depending on the action, there are two types of pathways:
- Systemic Action: once the product is absorbed, it is distributed and acts throughout the body.
- Local Action: a small amount of product passes into the bloodstream, and the effect is concentrated at the application site.
1. Inhalation Route: for a long time, inhalation was the most used form for all purposes. In non-medicinal use, despite the increased use of vaporizers, it is still the most widely used route. This route determines a rapid onset effect (in a few minutes the active ingredients go directly from the lungs to the brain), but the effects only last for a short duration. For this reason, in chronic diseases, to keep the symptoms under control, it is necessary to frequently repeat inhalation. This can be uncomfortable, and frequent use can increase the risk of developing a dependency on THC.
In my clinical practice, I reserve it as a “rescue” measure against increased pain, a critical phenomenon (e.g. epileptic, migraine or neuralgic crisis), or drug withdrawal syndrome.
Inhalation can be:
- Smoked; This form should not be considered for medical use and should be avoided in non-medical use, as it can generate several health risks, such as cancer, due to the generation of incomplete combustion residues, and chronic bronchitis.
- Steamed; Inhalation is carried out by means of special devices that, although they heat the product, do not burn it, since they reach temperatures in which the cannabinoid and terpenoid compounds are taken to steam. Care should be taken to use only vaporizers and products authorized for medicinal use in order to avoid damage derived from adulterants and contaminants such as recent fatal cases of respiratory disability in the USA.
2. Digestive Route: With the diffusion of cannabis oils, the use of this route has increased significantly. It has an onset action that ranges between 1.5 and 2 hours, and the effects lasts for several hours, so you can take it 1-3 times a day, every 8, 12 or even 24 hours.
Together with the mucosal absorption pathways (e.g. sublingual, nasal, rectal, vaginal) cannabinoids taken in this way are the most effective and prescribed for the treatment of chronic diseases. I personally do not recommend use in the form of food (brownies, gummies, lollipops, etc.) because the dosage is variable from one portion to another, and in the case of non-medical use it is the most frequent form of intoxication, as it is difficult to get the dosage correct.
Although the best known and most widespread form for the oral route are oils, as the industry and technology applied to the production of drugs based on cannabis and cannabinoids progress, other formulations such as softgels capsules, tablets, patches and other forms of prolonged-release can be found in the market.
3. Mucosal Route: includes different forms of administration in which absorption occurs directly from a mucosa (internal covering of the hollow organs) to the bloodstream, bringing the product directly to the targeted organs. It has a rapid onset effect (minutes), with a prolongation of the effect like that of the oral administration (several hours).
The formulations for the use of this route are nasal sprays and sublingual use, tinctures, suppositories, ovules and strips. These formulations are very effective in patients with digestive disorders (vomiting) or digestive intolerance, or when a rapid onset of action is required.
Some problems of these formulations are:
- Sprays and tinctures include alcohol, so in chronic use, they can cause damage to the mucous membranes (irritation, burn).
- Rectal absorption (suppositories) has variations in bioavailability (and consequently in effect) depending on how high each dose is absorbed (upper or lower hemorrhoidal plexus). This depends on how far the suppository migrates.
4. Percutaneous or Topical Route: cannabinoids are fatty substances so their absorption into the skin is very good. This is very useful route in the treatment of skin lesions such as dermatitis, psoriasis and acne, but care must be taken to select the most appropriate type of product for each disorder. For example, in acne, gels would be the most recommended form (as in any other lesion that has a risk of superinfection). Creams create a perfect environment for the development of some bacteria and shouldn’t be used in these cases.
With this route, good results are also achieved in cases of muscular and osteoarticular pain (e.g. contractures, joint inflammation). It is a complementary route for oral treatment of localized or multifocal pain.
In conclusion, when choosing a treatment and the route of administration it is important to evaluate all the factors involved with a doctor. The doctor will then be able to make a measured analysis of what the most appropriate treatment for each patient is following the guidelines of the rational use of medications.