I made this lengthy write up, but then I felt silly because it used a lot of limited research to try to suggest Cetirizine/Levocetirizine as a potential defense against ARDS. I actually thought it would make an interesting research proposal (if it is please let me know, want to be a part), given all the other hail marries that are happening, but then I realized I don’t even know how to make a research proposal because I am still on my journey to finishing medical school.
I guess in short (the much shorter version) this was my rationale.
EDITED TO INCLUDE REFERENCES
From a pathophysiological perspective, increased capillary permeability is a major contributing factor to ARDS. In COVID-19, infection from the SARS-CoV-2 seems to produce diffuse and comprehensive cellular damage throughout both lungs.1 Subsequent inflammatory processes become the key in the pathogenesis of ARDS. This diffuse damage releases pro-inflammatory cytokines, facilitating the inflammatory response.2 One pretty important cytokine seems to be interleukin-8 (IL-8), otherwise known as CXCL8. IL-8 is known to be a neutrophil chemotactic factor, causing both neutrophils and some other granulocytes to migrate to the site of infection, while also being a promoter of angiogenesis while also inducing physiological responses for migration and phagocytosis.3,4,5
In this way, IL-8 seems to be a mediator directly responsible for increasing vascular permeability and migration, which while typically is beneficial to the immune response, seems to play a significant role in acute lung injury, and further exacerbate the immune response. This increase in vascular permeability and migration seems to correspond with a major contributing factor for ARDS, and while it is no guarantee that it occurs in the case of this novel coronavirus, I did find some evidence of increased levels of IL-8 in ARDS as a result of tuberculosis, and other lung injuries.1,5
While hydroxyquinine and remdesivir may offer promising antiviral properties, perhaps we need further investigations as to ways we can potentially reduce ARDS onset, reduce ventilator usage and maybe improve outcomes.
Cetirizine/Levocetirizine are well known second generation anti-histamines, which is known to act as an H1-receptor antagonist, commonly used over the counter to treat allergies. It has also been able to demonstrate that it significantly counter-regulates interleukin-8, but also has been described specifically doing so from human lung cell of line A549 in vitro, likely through some other mechanism.7,9 Furthermore, in vivo, cetirizine has also demonstrated that it has been able to reduce Serum IL-8 levels in patients with atopic dermatitis and another review commented about IL-8 reductions during other allergies, which while not lung tissues, shows that it does seem to have an effect beyond the petri dish. 6,7,8