The evidence that hydroxychloroquine, chloroquine, or the hydroxychloroquine/azithromycin combination is an effective treatment for COVID-19 is getting weaker with every publication.
Some hospitals and medical centres that had been using the drugs as routine first-line treatments for COVID-19 patients have dropped them, reflecting the lack of evidence that they have a positive effect and growing evidence of harm.
Back in March, the Food and Drug Administration of the United States of America had granted an emergency use authorisation allowing doctors to prescribe chloroquine and hydroxychloroquine for COVID-19 patients in the US.
“We haven’t seen any clear evidence of benefit so we are not going to use hydroxychloroquine routinely anymore,” Vineet Chopra, head of hospital medicine at Michigan, said on April 2.
“That is based upon the fact that we have been prescribing hydroxychloroquine for a few weeks, did not see therapeutic benefit, but did see adverse effects.”
His view was echoed by Preeti Malani, chief health officer at the university.
“We have moved away from the antimalarial hydroxychloroquine,” she said on a video posted by the Journal of the American Medical Assn.
She added: “We were seeing toxicity – GI (gastrointestinal) side effects and liver toxicity.”
Brazilian researchers ended part of a trial of chloroquine treatment prematurely, when several patients subjected to high doses of the drug began to show heart irregularities.
The researchers validated fears about chloroquine’s tendency to increase the so-called QT interval of heart activity, a condition that could lead to life-threatening tachycardia, or rapid heartbeats.
A study that examined medical records of 84 COVID-19 patients treated with hydroxychloriquine and the antibiotic azithromycin at NYU found worrisome prolongation of the QT interval among nearly one-third of the patients, including especially serious increases among nine after as little as two days of treatment.
Four of the patients died, though there was no evidence that cardiac problems contributed to their deaths.
French pharmaceutical regulators detected the same phenomenon and issued a warning about prescribing hydroxychloroquine in COVID-19 patients.
They compiled reports of as many as 43 cardiac cases, including as many as seven involving sudden death associated with cardiac issues, in southern France.
“The risks, in particular cardiovascular, associated with these treatments are very present and potentially increased in COVID-19 patients,” the French pharmaceutical safety agency ANSM reported on Friday.
Solid conclusions about the efficacy of chloroquine or hydroxychloroquine will have to await large-scale clinical trials, but these may be long in coming.
Barring that or the emergence of any other large-scale, controlled trial, the evidence for the antimalarial drugs remains thin to the point of nonexistent, while evidence for the dangers mounts.