Question: What is the story with dexamethasone?

Answer: Dexamethasone is making a lot of news as a component of the drug therapy recently given to the President. Dexamethasone is a potent, long-lasting (24 hours) corticosteroid that is approximately 25x more potent than hydrocortisone. The main mechanism that corticosteroids are thought to help reduce COVID severity is that they reduce inflammation by tamping down the immune system so that it doesn’t attack itself (a la the cytokine storm we’ve learned about). Many questions still abound with regard to dexamethasone, but two recent studies — a clinical trial out of the UK and a meta-analysis conducted by the WHO — both indicate that dexamethasone can improve outcomes for patients with severe COVID-19.

Based on current evidence, WHO strongly recommends “for systemic (i.e. intravenous or oral) corticosteroid therapy (e.g. 6 mg of dexamethasone orally or intravenously daily or 50 mg of hydrocortisone intravenously every 8 hours) for 7 to 10 days in patients with severe and critical COVID-19…” and WHO also makes a conditional recommendation “not to use corticosteroid therapy in patients with nonsevere COVID-19.” As to non-severe COVID-19, one of the major concerns is that if given corticosteroids too early, the immune system could be hampered from doing its job and the patient would have a harder time fighting the virus.

Finally, if you want to read more, this JAMA editorial gives a good, brief run-down of the evidence and outstanding questions; this piece published in The Conversation gives a good overview of corticosteroids and COVID-19; and this Q&A from WHO gives more bite-sized information.