Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, has caused more than 6.4 million deaths to date.
a new one Research on cannabis and cannabinoids The study in the journal discusses the usefulness of cannabidiol (CBD) in treating the inflammatory symptoms of COVID-19. This treatment approach could help stop or slow the progression of COVID-19, which could reduce its severity and death rate.
To study: Cannabidiol as a treatment for symptoms of COVID-19? A critical review. Image credit: r.classen / Shutterstock.com
Introduction
COVID-19 is associated with a wide spectrum of presentations, from mild to life-threatening illness. The hyperinflammatory reaction to SARS-CoV-2 is thought to be responsible for severe symptoms involving multiple organ systems.
A wide range of drugs have been evaluated for their ability to mitigate the severity of COVID-19. These include dexamethasone, a potent corticosteroid with anti-inflammatory and immunosuppressive activity; remdesivir, a nucleoside analog that inhibits viral replication; hydrochloroquine, an immunomodulatory antimalarial drug, convalescent plasma containing virus-specific antibodies as well as SARS-CoV-2 monoclonal antibodies.
Of these, only dexamethasone has shown unequivocal improvement in outcomes in a specific patient group. In particular, this steroid has not been evaluated for its usefulness in the early treatment of COVID-19.
Meanwhile, remdesivir is only useful for hospitalized patients, with a relatively long course of treatment requiring parenteral administration. In addition, immunomodulators can have systemic effects.
Monoclonal antibodies are currently approved for use in patients with early disease who are at high risk for severe COVID-19.
Paxlovid and molnupiravir have received emergency use authorization (US) for the treatment of high-risk COVID-19 positive patients. These agents are only suitable for those with early symptoms who are not receiving any other treatment for severe COVID-19.
The need for safe and effective early interventions has driven research into potentially useful drugs for COVID-19. One of them is CBD, which acts on the CB1 and CB2 endocannabinoid receptors in the brain, as well as on the A2A adenosine receptors. These receptors are widespread in the human body.
CBD received approval in 2018 as an orphan drug for the treatment of a form of epilepsy. It is also known to have immunosuppressive and anti-inflammatory effects due to the expression of CB2 receptors on immune cells in the gut, lungs, and immune organs.
CBD in low doses can potentiate intoxication caused by other cannabis metabolites, specifically tetrahydrocannabidiol (THC); however, it appears to counteract these effects at high doses. Importantly, CBD is not known to cause dependence or addiction.
Side effects of CBD include drowsiness, fever, loss of appetite, abnormal behavior and euphoria. More research is needed to determine the relevance of these side effects after chronic use.
The current review summarizes the current knowledge on the effects of CBD on inflammation and respiratory symptoms related to COVID-19 from studies published between September and December 2020.
Results of the study
Of the nine papers eligible for inclusion in the study, five were in vivo studies and three were in vitro studies with human tissues. None of the animal models had COVID-19; however, they were used to determine the effect of CBD on acute lung inflammation or injury, asthma, and acute respiratory distress syndrome (ARDS).
CBD has been reported to decrease multiple inflammatory cytokines and reduce ARDS symptoms. Inflammatory infiltration of the lungs as well as a reduction in protein exudation, inflammatory cytokine levels, and myeloperoxidase levels were observed in response to CBD. Asthma-related inflammation was similarly reduced.
In human in vitro tissue models, CBD treatment was associated with lower expression of A2A receptors and reduced inflammation. Compared to dexamethasone, CBD reduced inflammatory signaling induced by lipopolysaccharide, which is a potent antigen that induces bacterial inflammation.
A single human randomized clinical trial (RCT) of CBD treatment in patients with mild to moderate COVID-19 was also available. To this end, no significant improvement was reported for CBD compared to controls for prevention of serious illness, reduced duration of symptoms, lower cytokine levels, reduced lung damage, hospitalization, or mortality. Psychological symptoms were also not different between groups.
A single open-label trial reported a reduction in burnout and emotional fatigue after CBD treatment in frontline workers with COVID-19. However, 10% of study participants reported serious adverse events, although all made a full recovery.
In a recent study not included in the current review, researchers identify some evidence of a replication inhibitory effect of CBD on SARS-CoV-2 that is mediated by the endoplasmic reticulum. They cited data from the National COVID Cohort Collaborative database, which showed lower rates of positive COVID-19 test results with CBD treatment.
Implications
Although current evidence does not support the use of CBD in the treatment of COVID-19, there is still an urgent need for further studies. These should explore different dosage levels with CBD of a specified purity for prophylactic and therapeutic use, given the promising anti-inflammatory activity observed with this molecule in vitro.
Drug interactions should also be explored, especially since the treatment of COVID-19 currently involves the use of many anti-inflammatory and immunomodulatory drugs.
Its anti-inflammatory properties could also be detrimental by suppressing the immune response, which could suppress the ability to fight infections, so the risk could be higher for viral and respiratory infections.”
Overall, there is no adequate evidence to support or reject CBD in the treatment of COVID-19.
Journal reference:
Holst, M., Nowak, D., & Hoch, E. (2022). Cannabidiol as a treatment for symptoms of COVID-19? A critical review. Research on cannabis and cannabidiol. doi:10.1089/can.2021.0135.