To the Editor:

Re “Trump Again Pushes Drug, Never Mind Expert Opinion” (news article, April 6):

Despite a lack of clear evidence of their efficacy, President Trump and others continue to strongly recommend unproven treatments for Covid-19. While azithromycin and hydroxychloroquine may eventually prove of benefit for this disease after proper scientific study, to date this has not occurred.

Individuals treated with both of these medications may have serious side effects, including cardiac toxicity, especially when used in combination. Demands for these medications may lead to their shortages so that they are unavailable to patients who need them for such diseases as rheumatoid arthritis and lupus for which their benefits have been proven.

Perhaps most important, patients’ demands for unproven medications may lead to their reluctance to enroll in properly conducted placebo-controlled clinical studies that may provide effective proven treatments for Covid-19.

David Siegel

Davis, Calif.

The writer is emeritus professor of medicine at the University of California Davis School of Medicine.