Hydroxychloroquine was brought to the attention of Trump by a French fraudster who published a totally flawed study in a journal controlled by someone who works for him after a one day peer review. The flaws were so pronounced that any of my first year medical students would have found them. Hydroxychloroquine has known serious side effects, including blindness. Used with azithromycin it can cause your heart to stop. A small but properly designed study in China found no effect of hydroxychloroquine on COVID-19.
Basically there is no evidence that it works and it is known to be potentially dangerous. Any doctor who wants to use it needs to become a clinical trial site so that we can properly determine whether it works or not — there are a lot of such trials underway. Meanwhile, the patients who REALLY need this drug — patients with lupus or rheumatoid arthritis — can’t get it. Oh, and the sickest patients can’t take hydroxychloroquine because it is only available as an oral medication. Thus it is to be expected that patients who take it have better outcomes — they aren’t as sick when they start!
Trump is completely irresponsible in promoting a potentially dangerous and untested drug combination. His flunkie Peter Navarro does not understand how to read and critique a clinical research study. Rudy Giuliani has in the past made a sufficiently ignorant statement about healthcare that I use it to teach medical students about how one can misunderstand certain types of bias in observational data and his promotion of these unapproved drugs sadly gives me more material.
There are far more promising treatments being tested now.