Peter Morley was outraged. Last weekend, President Trump had once again touted the anti-malaria drug hydroxychloroquine as a treatment for COVID-19, despite the protestations of medical professionals urging caution.

“It’s not going to hurt people,” he said, adding that the government had stockpiled 29 million pills to fight the virus. “It can help them, but it’s not going to hurt them. That’s the beauty of it. You see?”

As a patient advocate who struggles with lupus, an autoimmune disorder, Morley knew this was not just wrong, but dangerously so. He takes hydroxychloroquine(also known as Plaquenil) twice a day to manage his flare-ups. The drug, he says, is “lifesaving” to people in his community — yet thanks to Trump, many people have contacted him terrified, saying they’re unable to access it.

“I’m literally shaking,” he says.

In the rheumatology community, the response to Trump’s comments is “basically fury,” says Dr. Michael Lockshin, professor of medicine and director of the Barbara Volcker Center at Hospital for Special Surgery.

“It is extremely dangerous to promote an unproven treatment and with that, deprive patients who are doing well on the medication from having it,” he says.

Hydroxychloroquine is an anti-malarial drug that has been used to treat lupus and rheumatoid arthritis since the 1940s and 1950s, says Lockshin. It has some dangerous side effects, including retinal damage and increased risk of cardiac arrest (and indeed, some clinical trials in Sweden have been halted when patients started developing such side effects in response to the drug). Yet for many people with lupus, Morley says, it can be “absolutely lifesaving.”

For those who have been regularly taking the drug and have to stop taking it, flareups can be severe, says Lockshin, even possibly deadly depending on the severity of one’s symptoms. Ali Brown, a lupus patient in Ellensburg, Washington, says that the last time she stopped taking Plaquenil, she ended up in the hospital with a double kidney infection and sepsis.

“I don’t panic very often,” she says. “When the pandemic started, I didn’t rush out and buy a bunch of toilet paper or food, but [the prospect of being without my medication] scares me.”

Currently, there is no proven treatment or vaccine for COVID-19; though there is some anecdotal evidence to suggest hydroxychloroquine may be helpful for treating COVID-19 patients, Dr. Anthony Fauci of the National Institutes of Health has cautioned against touting it as a miracle drug, as President Trump has. “In terms of science, I don’t think we can definitively say it works,” Fauci told CBS’s Face the Nation. “The data are really just at best suggestive.”

Lockshin also says he is skeptical about its efficacy for COVID-19 patients. “If it were a game-changer we would’ve seen something. But the disease [in New York City] is as severe before the talk about hydroxychloroquine as it is after,” he says. “None of us are seeing any amelioration with this drug.”

Despite such limited evidence, many pharmacies and hospitals have begun purchasing “excessive amounts” of the medication, per a condemnatory joint statement from the the American Medical Association, the American Pharmacists Association and the American Society of Health-System Pharmacists.

This has had the effect of making the drug less accessible for patients for whom it is regularly prescribed, according to many people with lupus on Twitter, who have said they are now unable to take the drug that they have relied on to manage flare-ups. “Thousands of people have reached out to me fearful of losing access their medication,” says Morley, adding that many are rationing it for fear of worse future shortages.

Brown says her pharmacy only gave her a month-long rather than a 90-day supply, and Lockshin says he has heard of some pharmacies refusing to prescribe the drug for anything other than COVID-19, even for patients who have been on it for a long time. “There is absolutely panic,” he says.

Trump’s pushing of hydroxychloroquine is all the more dangerous in light of another message he pushed on Saturday, that people with lupus who take the medication are immune to COVID-19 (largely based on anecdotal evidence from Chinese doctors). Lockshin says this is false, and that he personally knows of COVID-19 patients currently in the ICU who have been diagnosed with lupus. Such misinformation could also put people with autoimmune disorders even more at risk by encouraging them not to take the medication. “If I were to develop pleurisy [inflammation of the lungs], in this crisis that we’re in I could end up in the hospital. And being in a hospital could literally kill me,” he says.

Perhaps the ultimate irony of Trump’s messaging about hydroxychloroquine is that it could have the effect of hurting marginalized people who are already at heightened risk of contracting COVID-19, at least in New York City, the current U.S. epicenter of the virus. Previous data shows that communities of color tend to have higher rates of COVID-19, and women of color in particular are overrepresented among lupus patients, says Lockshin. “It’s accurate to say marginalized people will suffer disproportionately because of the President’s remarks,” he says.