The malaria drugs hydroxychloroquine and chloroquine did not help coronavirus patients and may have done harm, according to a new study based on the records of nearly 15,000 patients who received the drugs and 81,000 who did not.
Some were also given the antibiotic azithromycin, or a related medicine.
Hydroxychloroquine is the drug that President Trump has advocated, and that he said he has been taking in hopes of preventing coronavirus infection.
People who received the drugs were more likely to have abnormal heart rhythms, according to the study in the The Lancet. They were also more likely to die. But the findings were not definitive, because the study was observational, meaning that the patients were not picked at random to receive the drug or not, and may have had underlying differences that affected their outcomes.
The findings match those of several earlier observational studies that also found no benefit and possible harm from the drugs, and that have led some medical centers to stop recommending their use.
The new study is based on data from 96,032 coronavirus patients from 671 hospitals around the world. The authors say it is the most comprehensive study to date. While acknowledging the limitations of observational studies, they write, “our findings suggest not only an absence of therapeutic benefit but also potential harm with the use of hydroxychloroquine or chloroquine drug regimens,” with or without antibiotics, in hospitalized patients with Covid-19.
Because of possible underlying differences between treated and untreated patients, this type of study cannot provide definitive evidence about drug safety and effectiveness. Even so, the authors recommended that