Furthermore, patients who truly need these medications for serious conditions like lupus are going without treatment. Some states have been forced to limit dispensing them.

Doctors have known for decades that chloroquine and related medications like hydroxychloroquine and mefloquine can cause psychiatric side effects even after just one dose. While some patients experience mild anxiety, insomnia and nightmares, others have severe symptoms like personality changes, paranoia, hallucinations and even suicidal thoughts.

Here’s one example of the impact these drugs can have: A 74-year-old woman, with no mental health history and otherwise doing well, was admitted to a psychiatric facility because she insisted her neighbors were shooting electromagnetic waves into her apartment. She said they were using these waves to spy on her and to destroy her brain. Her doctors were puzzled — until they discovered that she had recently started on chloroquine to treat her arthritis. Once the medication was stopped, she fully recovered.

Mental health changes are not the only risks we see. Chloroquine and azithromycin can also affect the heart’s normal rhythm by prolonging the “QT interval,” the time it takes for the large chambers in the heart to relax after pumping out blood. If the QT interval becomes too long, it can lead to abnormal rhythms, or arrhythmias, where the heart starts beating out of control. This change can cause death. The patients at risk of this are the same ones who are most vulnerable to Covid-19: the elderly and those with chronic illnesses. So while the president may claim these medications are “not killing people,” we know and have seen that in some cases they do.

All medications have side effects, and nothing is without risk. This is why our F.D.A. approval process, though long, exists to ensure the safety and efficacy of the medications we prescribe. We rely on the F.D.A.’s information, and as physicians, we carefully weigh the pros and cons of each medication for each patient before prescribing.