The 75 years of data we have on chloroquine and 65 years on hydroxychloroquine provide ample evidence that these sister compounds are neither miracle drugs nor universally safe.

Yet President Trump continues to use his bully pulpit to push them as though they are. On Monday, he stunned reporters by announcing he is taking hydroxychloroquine to prevent covid-19 — the disease caused by the novel coronavirus. Then he repeated his own false claims about its efficacy.

“A lot of good things have come out about the hydroxy,” he said. “I happen to be taking it.” He said he started it because “there’s a very good chance” the drug works against infections and “especially early on” as a preventive measure. Then he repeated his own misguided belief that people who want to take it have little to fear: “You’re not going to get sick or die.”

The White House later released a letter from Sean Conley, Trump’s physician, saying he and the president had had “numerous discussions” about the evidence “for and against” hydroxychloroquine since Trump’s personal valet tested positive for covid-19, and they had “concluded that the potential benefit from treatment outweighed the relative risks.” The letter did not specifically confirm Trump is taking the medication.

All this defies medical evidence and common sense. Trump’s continued obsession with hydroxychloroquine has reached dangerous depths. Even usually loyal Fox News called his announcement “irresponsible,” given how much has been learned since March, when Trump first used news conferences and Twitter to tout the drug to the public.

Then, Trump pressured the Food and Drug Administration to grant limited emergency approval for use of chloroquine and hydroxychloroquine against covid-19, even though no human studies showed they worked. Prescriptions for both skyrocketed, creating shortages and conjuring speculation about Trump and his allies profiteering. (The FDA has since warned against the drugs’ use outside of hospital settings.)

The president’s early enthusiasm was marginally understandable. Rumors on Twitter amplified by celebrities, including Tesla co-founder Elon Musk, touted chloroquine as a possible miracle cure for this tricky virus we all fear. The rumors were based on flawed studies released in France and China that suggested hydroxychloroquine might shorten hospital stays. The studies were too small and anecdotal to be of value, and the French one has since been discredited. But the damage was done.

When Trump called the drug a “game changer,” I assumed he had fallen victim to the charlatans and his own confirmation bias. He so wanted a drug to save us from the nightmare we’re now living that he did not listen to the experts’ warnings about the studies and chloroquine’s well-known side effects — which range from minor intestinal disruptions and skin rashes to serious psychosis and even heart failure. This drug would be no panacea.

Much has changed in the past two months; we now have plenty of reasons to doubt these drugs. Which makes Trump’s relentless and myopic obsession with them all the stranger.

There’s already plenty of evidence that Trump’s offhand remarks about treatments for the coronavirus lead people to take dangerous actions. Look at what happened after he wondered out loud on April 23 whether injecting disinfectants might cure covid-19. In just days, poison control centers nationwide — including in California, Illinois, Kansas, Maryland, Massachusetts, Michigan and New York — had significant upticks in cases of toxic chemical exposure. People gargled with bleach, used detergent as a sinus rinse and drank disinfectant. Governors, public health officials and even the makers of Lysol had to put out statements begging the public to not ingest cleaning products. The American Association of Poison Control Centers later reported poisonings from disinfectants were up 121 percent in April over April 2019, and poisonings from bleach were up 77 percent.

Trump’s nonsensical comments about disinfectants were a mistake, and he knew it. He even tried to pretend he wasn’t serious. But he was dead serious Monday about hydroxychloroquine. Part of it may have been a show to try to discredit Rick Bright, the government’s former top vaccine expert, who told Congress last week he was fired because he doubted the value of hydroxychloroquine and had resisted pressure to redirect money to study it. For Trump to be right, Bright must be wrong. So Trump’s surprise announcement may have been an attempt to tip public sentiment in his favor.

The other part of it, though, is that Trump seems to want everyone to take hydroxychloroquine.

Which is just so curious. Why obsess about this one drug? Why not remdesivir, for which studies are showing consistent positive results and about which experts are actually excited? Or two new possibilities that show promise, both already approved by the FDA to treat worms and asthma? Or any of the 47 other FDA-approved drugs that a team of researchers screened and found to have strong action against the coronavirus (the results of which were published in Nature on April 30)? Granted, these screenings were done against the virus in petri dishes. But the only solid evidence that hydroxychloroquine works against the virus is from similar in vitro studies. On the other hand, none of these other studies are getting attention on Fox News and right-wing Twitter, which seems to be where Trump gets his medical information.

The real tests will be on humans, and people with autoimmune disorders are already helping scientists learn how these medications do or don’t work on the coronavirus. About 60 to 70 percent of lupus patients and 10 to 25 percent of rheumatoid arthritis patients tolerate hydroxychloroquine and take it as a long-term maintenance drug. At least 209 of them have reported to the Rheumatology Alliance Global Registry database that they contracted covid-19 while on the drug. These patients anecdotally suggest it does nothing to prevent the disease. Larger clinical trials to measure the drug as a prophylactic are underway. One with more than 3,000 patients at the University of Minnesota started in March and is scheduled for completion this month.

On treatment, some unnerving studies suggest hydroxychloroquine may do nothing, or even do harm. One published in the New England Journal of Medicine on May 7 with more than 800 hospitalized patients showed no benefit from the treatment. One study involving 368 patients at a Veterans Affairs hospital in Virginia showed higher death rates in those taking the drug. A large recent study from China originally showed some promise for the drug, but the data turned out to be flawed.

One thing that is indisputable, based on information dating to World War II, is that these chloroquine-derived drugs are treacherous because they have a narrow therapeutic index — which means the dose needed for treatment is close to the toxic dose. This is why doctors use them so carefully.

Trump seems unable to grasp this basic concept. And he doesn’t seem interested in the dangers.

What is the public to conclude now that Trump says he’s taking hydroxychloroquine? If the past is any indication, more people will decide to take it. But unlike Trump, most will do so without the benefit of an in-house doctor and 24-hour monitoring to check for side effects — such as blindness, kidney failure, suicidal thoughts and heart attacks. Trump never uses his bully pulpit to warn people about what they’re stepping into, should they take his medical advice. But he should. It’s the least he can do.

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