President Trump’s announcement on Friday that he tested positive for the coronavirus has reignited an online fervor over hydroxychloroquine, a drug repeatedly promoted and taken by Mr. Trump despite a lack of evidence that it effectively treats or prevents Covid-19.
Advocates of the drug have taken to Twitter and Facebook over the past few days to recommend hydroxychloroquine as a course of treatment for Mr. Trump. Among them was Representative Andy Biggs, a Republican of Arizona. On Friday, Mr. Biggs passed on his well wishes to the president on Twitter before encouraging him and the first lady, Melania Trump, who also contracted the coronavirus, “to take hydroxychloroquine to assist with their recoveries.”
All of the online activity means it’s a good time to sort through what we know about hydroxychloroquine.
The drug has long been used to treat malaria, lupus and rheumatoid arthritis. At the start of the pandemic, a handful of small, poorly designed studies suggested that it could block the coronavirus from replicating in cells.
Since then, the data on hydroxychloroquine’s effectiveness against the virus has been mixed. The early, seemingly promising results, bolstered by political pressure, prompted the Food and Drug Administration to grant the drug an emergency authorization for use in very sick Covid-19 patients. Follow-up studies, however, found the drug neither sped recovery nor prevented healthy people from contracting the coronavirus or progressing to serious disease.
The F.D.A. ultimately revoked its emergency approval. The agency now warns that hydroxychloroquine can cause dangerous abnormalities in heart rhythm in coronavirus patients. Researchers have also conducted large reviews concluding that hydroxychloroquine does not benefit Covid-19 patients, and have reaffirmed the risks of side effects in these individuals.
Still, the drug has been championed by some — including President Trump, who praised it through the summer.
So what treatment is Mr. Trump, who has been hospitalized at Walter Reed military hospital, actually receiving?
His doctor, Sean P. Conley, has said that Mr. Trump received an infusion of an experimental antibody treatment developed by drug maker Regeneron, and was also taking zinc, vitamin D, melatonin, aspirin and a generic version of the heartburn treatment Pepcid. Dr. Conley has also said the president has begun a five-day course of remdesivir, an antiviral drug given emergency use authorization from the F.D.A. to treat hospitalized Covid-19 patients. And on Sunday, Dr. Conley said that Mr. Trump had been given the steroid dexamethasone, which has been shown to help patients who are severely ill with Covid-19, but can be harmful for patients with mild or moderate cases of the disease.
Hydroxychloroquine was not mentioned by Mr. Trump’s medical team. That prompted some on Twitter to speak out on what they saw as an omission in Mr. Trump’s treatment.