The US Food and Drug Administration on Friday warned of the risk of heart problems in patients taking antimalarial drugs touted by Donald Trump as a potential treatment for Covid-19.
The US drug regulator said on Friday that hydroxychloroquine or chloroquine, whether taken alone or in conjunction with the antibiotic azythromycin, could lead to heart rhythm problems for some patients.
Stephen Hahn, the FDA commissioner, said in a statement: “While clinical trials are ongoing to determine the safety and effectiveness of these drugs for Covid-19, there are known side-effects of these medications that should be considered. We encourage healthcare professionals making individual patient decisions closely screen and monitor those patients to help mitigate these risks.”
Just hours later, however, Mr Trump repeated his fulsome praise for the drug’s potential as a coronavirus treatment. He told reporters in the Oval Office: “I did speak with the president of Honduras just a little while ago . . . and he said they used the hyrdoxychloroquine and he said the results are so incredible.”
The FDA has licensed hydroxychloroquine for use against malaria, and has granted an emergency authorisation for it to be used in clinical trials and in certain controlled hospital settings against the coronavirus. But it reiterated on Friday that the drug should not be used outside those contexts, saying that it was “aware of increased use of these medicines through outpatient prescriptions”.
The US president’s push for people to use hydroxychloroquine has already caused ructions within his own administration. Earlier this week Rick Bright alleged he had been dismissed as the director of the Biomedical Advanced Research and Development Authority because of his doubts about the drug’s efficacy against Covid-19.
The FDA said in its warning that hydroxychloroquine should only be administered as part of a clinical trial or in certain controlled situations within a hospital. The regulator’s warning echoed concerns about the drug that were raised two days earlier by the National Institutes of Health, which said the combination of hydroxychloroquine and azithromycin could poison patients.
The European Medicines Agency, which regulates drugs in the EU, issued a similar message on Thursday about the “risk of serious side-effects”, including heart rhythm problems, in patients taking chloroquine and hydroxychloroquine to treat Covid-19.
A study published Friday in the Journal of the American Medical Association appeared to bolster those warnings. It cautioned against prescribing high doses of chloroquine diphosphate, after finding patients with severe coronavirus were more likely to die after taking them.
The reports’ authors found higher doses of chloroquine appeared to result in patients with severe coronavirus dying, and added: “The higher CQ [chloroquine] dosage should not be recommended for critically ill patients with Covid-19 because of its potential safety hazards, especially when taken concurrently with azithromycin and oseltamivir.”