Glucocorticoids and COVID-19.

Coronavirus Disease 19 (COVID-19) is associated with high morbidity and mortality rates globally, representing the greatest health and economic challenge today. Several drugs are currently approved for the treatment of COVID-19. Among these, glucocorticoids (GCs) have received particular attention due to their anti-inflammatory and immunosuppressive effects. In fact, GC are widely used in current clinical practice to treat inflammatory, allergic and autoimmune diseases. Major mechanisms of GC action include inhibition of innate and adaptive immune activity. In particular, an important role is played by the inhibition of pro-inflammatory cytokines and chemokines, and the induction of proteins with anti-inflammatory activity. Overall, as indicated by various national and international regulatory agencies, GCs are recommended for the treatment of COVID-19 in patients requiring oxygen therapy, with or without mechanical ventilation. Regarding the use of GCs for the COVID-19 treatment of non-hospitalized patients at an early stage of the disease, many controversial studies have been reported and regulatory agencies have not recommended their use. The decision to start GC therapy should be based not only on the severity of COVID-19 disease, but also on careful considerations of the benefit/risk profile in individual patients, including monitoring of adverse events. In this review we summarize the effects of GCs on the major cellular and molecular components of the inflammatory/immune system, the benefits and the adverse common reactions in the treatment of inflammatory/autoimmune diseases, as well as in the management of COVID-19.

Histamine receptors and COVID-19.

OBJECTIVE: Reports that the over-the-counter histamine H2 receptor antagonist famotidine could help treat the novel coronavirus disease (COVID-19) appeared from April 2020. We, therefore, examined reports on interactions between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and histamine receptor antagonists. METHODS: A systematic literature search was performed by 19 September 2020, and updated on 28 October 2020, in PubMed, Scopus, Cochrane Library and Google Scholar using (COVID-19 OR coronavirus OR SARS-CoV-2) AND (histamine antagonist OR famotidine OR cimetidine). ClinicalTrials.gov was searched for COVID-19 and (famotidine or histamine). RESULTS: Famotidine may be a useful addition in COVID-19 treatment, but the results from prospective randomized trials are as yet awaited. Bioinformatics/drug repurposing studies indicated that, among several medicines, H1 and H2 receptor antagonists may interact with key viral enzymes. However, in vitro studies have to date failed to show a direct inhibition of famotidine on SARS-CoV-2 replication. CONCLUSIONS: Clinical research into the potential benefits of H2 receptor antagonists in managing COVID-19 inflammation began from a simple observation and now is being tested in multi-centre clinical trials. The positive effects of famotidine may be due to H2 receptor-mediated immunomodulatory actions on mast cell histamine-cytokine cross-talk, rather than a direct action on SARS-CoV-2.