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The Food and Drug Administration on Friday cautioned against the use of hydroxychloroquine, a malaria drug originally approved in 1955, to treat Covid-19 outside of the hospital or in the setting of a clinical trial. The drug has been repeatedly touted by President Trump as a potential treatment.

In a drug safety communication meant for health care providers, the FDA said it is “aware of reports of serious heart rhythm problems” in patients with Covid-19 treated with hydroxychloroquine or an older drug, chloroquine. The agency said it seeks to “remind health care professionals and patients of the known risks associated with both hydroxychloroquine and chloroquine.”


“We understand that health care professionals are looking for every possible treatment option for their patients and we want to ensure we’re providing them with the appropriate information needed for them to make the best medical decisions,” FDA Commissioner Stephen Hahn said in a statement. He said that the FDA encourages health care professionals to “closely screen and monitor” those patients who doctors decide to give the drugs to mitigate potential risks.

Hydroxychloroquine is a widely available generic drug, and manufacturers including Novartis and Teva have donated millions of doses. It was one of the first medicines identified in lab tests to have potential to fight the coronavirus SARS-CoV-2, which causes Covid-19.

Early reports, including several from a controversial French researcher, Didier Raoult, led to early enthusiasm for the drug. President Trump repeatedly expressed enthusiasm for it during White House press briefings, and the drug was commonly mentioned by television commentators on Fox News. 


But medicines that show promise in early studies frequently show no benefits in clinical trials, and data on the medicine have been more mixed, with some small studies showing a benefit, others showing none, and a few indicating that patients might be harmed by the drug.

In a paper published in Nature Medicine Friday, researchers at New York University wrote that of 84 consecutive patients treated with the combination of hydroxychloroquine and azithromycin, an antibiotic, 9 had changes in the QT interval, a measure of electrical pulses in the heart, that would put them at heightened risk of a severe arrhythmia or sudden cardiac death.

“Hydroxychloroquine and chloroquine can cause abnormal heart rhythms such as QT interval prolongation and a dangerously rapid heart rate called ventricular tachycardia,” the FDA said in its warning. “These risks may increase when these medicines are combined with other medicines known to prolong the QT interval, including the antibiotic azithromycin, which is also being used in some COVID-19 patients without FDA approval for this condition.”

The agency clearly states in the document that use should be restricted. “To decrease the risk of these heart problems that can be life-threatening, we are warning the public that hydroxychloroquine and chloroquine, either alone or combined with azithromycin, when used for COVID-19 should be limited to clinical trial settings or for treating certain hospitalized patients under the EUA,” the agency said. “FDA will continue to investigate risks associated with the use of hydroxychloroquine and chloroquine for COVID-19, and we will communicate publicly when we have more information.”

The EUA, or emergency use authorization, was an earlier clearance granted on March 30 to allow the use of hydroxychloroquine from a government stockpile to treat patients in the hospital. In an April 14 article in the New England Journal of Medicine, two doctors at Harvard’s Brigham and Women’s hospital, Benjamin N. Rome, and Jerry Avorn, wrote that the EUA was “widely yet incorrectly reported by Trump and others as meaning that the FDA had approved the drugs for this indication.” In the article, Rome and Avorn warned: “These developments represent fundamental threats to the U.S. drug-evaluation process.”

Lacking other options, doctors appear to have used hydroxychloroquine widely in hospitalized patients, and its use was recommended in guidelines produced by major hospitals. However, the drug’s exact benefit has been unclear, with some physicians reporting dramatic results and others not seeing much benefit at all.

One problem is that exactly how sick patients become with the disease is unpredictable, meaning that results can depend as much on which patients are selected for a study as which treatments are used. The only way to be sure is to randomly assign patients to a placebo.

More than 133 studies are currently running to determine if hydroxychloroquine is effective in various stages of Covid-19. Some results are expected soon, including results from a University of Minnesota study that aims to see if the drug can prevent infection in health care workers. Recently, Novartis announced it would fund its own study of the drug. It is also being studied in large studies run by the U.K. government and the World Health Organization.

“The FDA will continue to monitor and investigate these potential risks and will communicate publicly when more information is available,” Hahn said in his statement.

  • In 1950s and 1960s, we were required to get Smallpox innoculations and Polio vaccines. These diseases were killers. But because everyone had to get shots, diseases were eliminated. Now with Flu vaccine only 43% of Americans get shot. Even less for Pneumococcal pneumonia. This is just insane. Hopefully people will get smart and get shots for these terrible respiratory illnesses. I wonder how many people who have died from Covid19, did not get flu or pneumococcus shots. CDC Dr Redfield probably has a good idea but hasn’t told public yet. CDC is stressing get shots. Too bad it is not mandatory like in 50s and 60s.

    • Large DoD Flu vaccine study showed it increased incidence of coronaviruses and pneumonia.

      “Study of flu vaccine and its effect on incidence of viral respiratory illness.”
      Vaccine. 2020 Jan 10;38(2):350-354. doi: 10.1016/j.vaccine.2019.10.005. Epub 2019 Oct 10.
      Receiving influenza vaccination may increase the risk of other respiratory viruses, a phenomenon known as virus interference. Test-negative study designs are often utilized to calculate influenza vaccine effectiveness. The virus interference phenomenon goes against the basic assumption of the test-negative vaccine effectiveness study that vaccination does not change the risk of infection with other respiratory illness, thus potentially biasing vaccine effectiveness results in the positive direction. This study aimed to investigate virus interference by comparing respiratory virus status among Department of Defense personnel based on their influenza vaccination status. Furthermore, individual respiratory viruses and their association with influenza vaccination were examined.
      We compared vaccination status of 2880 people with non-influenza respiratory viruses to 3240 people with pan-negative results. Comparing vaccinated to non-vaccinated patients, the adjusted odds ratio for non-flu viruses was 0.97 (95% confidence interval (CI): 0.86, 1.09; p = 0.60). Additionally, the vaccination status of 3349 cases of influenza were compared to three different control groups: all controls (N = 6120), non-influenza positive controls (N = 2880), and pan-negative controls (N = 3240). The adjusted ORs for the comparisons among the three control groups did not vary much (range: 0.46-0.51).
      Influenza vaccination and respiratory virus interference among Department of Defense personnel during the 2017-2018 influenza season.
      Receipt of influenza vaccination was not associated with virus interference among our population. Examining virus interference by specific respiratory viruses showed mixed results. Vaccine derived virus interference was significantly associated with coronavirus and human metapneumovirus; however, significant protection with vaccination was associated not only with most influenza viruses, but also parainfluenza, RSV, and non-influenza virus coinfections.”

    • I would have to see much more evidence that influenza vaccine would make Covid19 infection greater. Does not make sense. The opposite might make sense. Are you advocating not getting flu vaccine and accept the increased probability of getting very sick or dying from flu? Robbing Peter to pay Paul…

  • If you can get a fullface NBC mask, get it and wear it. Next get an N99 or P99 mask. Test your mask when wearing it by putting alcohol on rag and see if you can smell it through mask. Do the same with cigarette smoke or Lysol. If you smell the smoke or chemicals, your mask and/or fit is no good.

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