Does Treatment with CBD-Rich Cannabis Oil Cause Less Side Effects?
One theory is that treatment with CBD-rich strains (in general, or with CBD-rich cannabis oil specifically) causes fewer adverse effects and is more effective in treating cancer symptoms and chemotherapy’s side effects. In practice, a study examining the effectiveness of treatment and the rate of adverse effects in oncology patients who were treated with THC-rich strains (mainly by inhalation) compared to patients who were treated with CBD-rich strains (mainly orally using oil) found no significant clinical differences between the treatments in their effectiveness or safety1.
Is CBD-Rich Cannabis Oil Absorbed Faster?
A second theory argues that medical cannabis oil in sub-lingual administration is absorbed directly into the bloodstream from the oral cavity and is safer than the administration of inflorescence via inhalers/vaporizers/cigarettes. Cannabinoids are “lipophilic” substances. Therefore, they are mixed with olive/coconut/sesame/canola oil for medical treatment purposes. Their sublingual absorption directly into the bloodstream, which is supposed to be rapid in an area saturated with blood vessels such as under the tongue – is limited, and it is estimated that in practice, most of the oil is swallowed and enters the digestive tract.
This is demonstrated in a study where two types of medical cannabis oils were administered (one THC-rich and the second with an equal ratio of THC:CBD)2. Blood test results in this study showed that the THC and CBD levels in the blood reached their maximum after three hours or more, A result that can indicate absorption through the digestive tract. In addition, the researchers reported a significant rate of side effects; For THC-rich cannabis oil, side effects were reported among approximately 67% of the subjects, while for the cannabis oil with the equivalent rates of THC and CBD, side effects were reported among approximately 75% of the subjects. These side effects were mainly related to the digestive system – another finding indicating that probably a large portion of the cannabis oil goes directly into the digestive tract.
In comparison, in an observational study (cohort study) conducted among patients who inhaled THC-rich cannabis using the SyqeAir Inhaler and Cartridge, 41% of the subjects (59 out of 143 patients) reported (at least) one treatment-related side effect. Most of the adverse effects reported in this study were reported in the initial phase of the treatment. Six months later, among the patients who continued using the SyqeAir Inhaler and Cartridge, only 1% of them reported side effects related to treatment with medical cannabis3.
Medical Cannabis for Crohn's or Colitis Patients:
Is CBD-Rich Medical Cannabis Oil Suitable for Treating Inflammation?
There is another theory that consuming Cannabidiol-rich oil (CBD) is suitable for treating inflammation and can reduce the inflammatory process in patients suffering from inflammatory bowel disease. This belief has been tested in a study examining Ulcerative Colitis patients. Although patients reported positive subjective effects, no objective improvement in the patients’ intestinal inflammation was observed at all during colonoscopy4.
Another study entitled “Low-Dose Cannabidiol Is Safe but Not Effective in the Treatment for Crohn’s Disease” with the participation of Crohn’s disease patients reached similar findings. It was a randomized, double-blinded, placebo-controlled trial – a clinical study in which both the attending physicians and the patients/subjects are unaware of which group each patient belongs to, nor whether the patient receives the experimental treatment or the placebo. The findings show that CBD-rich oil is safe for treatment but ineffective in treating the inflammation associated with the disease. At the same time, the issue of safety should be questioned since the side effect of nausea as a result of the treatment was reported as 3 (on average) on a scale of 0-3.
Is Treatment with Cannabis Oil Effective and Safe in the Long Term?
A group of researchers from a university in Australia published an article about a two-year study on the effectiveness and safety of treatment with medical cannabis oil. The study began with the participation of 3,961 patients: about 51% of them consumed “balanced” oil (equal ratio of THC & CBD), about 31% consumed pure CBD oil, about 14% consumed THC-rich oil, and about 4% consumed CBD-rich oil. This is the longest study to date that has examined the effects of cannabis oil treatment. By the end of the study, after two years, only 431 patients remained – a dropout rate of about 90%.
Although a statistical improvement was reported in the tested indices, no significant clinical improvement was observed. Only the patients who remained in treatment after one year from the beginning of the study experienced a reduction in pain intensity from 5.53 (before treatment) to 4.20 – a decrease of 1.33 on a scale of 0-10, and another decrease to 4.31 after two years of treatment – a decrease of 1.22 on a scale of 0-10.
Also, despite the low doses of THC (about 20 mg per day), about 37% of the patients reported at least one side effect: drowsiness, dry mouth, lethargy, nausea, vomiting, difficulty concentrating, “high” feeling, diarrhea, increased appetite, headaches, anxiety, vivid dreams, and hallucinations. 2% of these adverse effects were defined as severe and required dose reduction or treatment discontinuation. Two specific adverse effects – hallucinations and mania – were also defined as severe and required hospitalization or life-saving intervention5.
Medical Cannabis Oil and Lower Back Pain
An open observational study conducted at the Rabin Medical Center (Beilinson and Sharon) compared the effect of inhaling THC-rich cannabis and of taking CBD cannabis oil. 24 patients who suffer from lower back pain combined with neuropathic pain (spinal stenosis or herniated disc) participated in the study.
The study was 24 months long and conducted in the following manner: a wash-out month (“waiting period”) for patients with a former license for cannabis, a 10-month treatment using CBD-rich cannabis oil, another wash-out month, and finally, a 12-month treatment using THC-rich cannabis via smoking. Three of the patients chose not to participate in the first part of the study in which oil was administered but participated in the second part of the study in which inflorescence was administered by inhalation. Participants were allowed to use additional painkillers, which included, among others, opiates.
The findings of the study showed that during the CBD oil period, the reduction in pain intensity was negligible and insignificant (decrease of 12.3%), and after switching to THC-rich inhaled cannabis, a more significant reduction in pain intensity was observed – 53% decrease compared to the beginning of the study. It is evident from this study that cannabis oil, and especially CBD oil, is clinically less effective for treating chronic pain. Note: the researchers did not report whether there was a change in the use of other painkillers, including opiates, following the cannabis use6.
Cannabis Oil: Pros and Cons
Cannabis oil is comprised of an extract of natural inflorescence mixed with oil. It is one of the most common routes of administration, along with inflorescences (delivery using an Inhaler, vaporizer, or smoking)7.
Advantages of using cannabis oil:
- No smoking damage
- Effect duration is longer compared to cannabis administered by inhalation: 6-8 hours from the onset of action
Disadvantages of using cannabis oil:
- No metered dosing: Although the dose is given by drops, it cannot be determined that all the drops are equal in amount. Therefore, with each intake, the patient may experience a different level of pain reduction and side effects
- Delayed effect: Unlike with inhalation, the time that passes from the moment of ingesting the cannabis oil to the onset of action is longer, about 1-3 hours
- Varying effect: Depends on the contents of the stomach
- Risk of overdosing, which results in side effects: Patients who wait a long time for the effect to start might think that the dose they took “doesn’t work” and will take another drop or more as a boost – which increases the risk of side effects once the effect starts
- Non-uniformity in treatment: Variations between the concentrations of the active ingredients between products of different brands, as well as between the different batches of the same product, result in a non-uniform and inconsistent treatment which provides a different effect every month
- Cannot provide a solution for breakthrough pain: Due to the delayed effect
- Allergies: It is necessary to make sure that the patient is not allergic to the type of oil within the extract
- Almog S, et al. European Journal of Pain, 24(8), p1505-1516.
- Guy G. et al. 2004. Journal of Cannabis Therapeutics, 3(4), p121-152
- Aviram J. et al. 2022. Pain reports 7(3).
- Naftali, T, et al. 2017. Digestive diseases and sciences, 62, 1615-1620.
- Vickery A. et al. 2022. PLoS ONE, 17(11).
- Robinson D. 2022. Rambam Maimonides medical journal 13(4)
- Aviram, J. (2021). European Journal of Pain, 25(2), 359-374.
