Treatment for Covid-19 with the antimalarial drug hydroxychloroquine, either with or without the antibiotic azithromycin, offers no benefit for Covid-19 patients, according to a large observational study.


The research, published in the journal The Lancet, analysed data from nearly 15,000 patients with Covid-19 who received chloroquine or its analogue hydroxychloroquine, taken with or without the antibiotics azithromycin or clarithromycin, and 81,000 controls.


According to the researchers, including Mandeep Mehra from Brigham and Women's Hospital in the US, Covid-19 patients on these drug regimens, experienced an increased risk of serious heart rhythm complications.


The scientists said these drugs should not be used to treat Covid-19 patients outside of clinical trials until results from randomised clinical trials are available to confirm their safety and efficacy for Covid-19 patients.


They explained chloroquine, an antimalarial drug and its analogue, hydroxychloroquine, are commonly used to treat autoimmune diseases including lupus and arthritis.


Both these drugs have a good safety profile as treatments for those specific conditions, and the current research said these patients should not stop taking these drugs if they are prescribed for approved conditions.


While these drugs have shown antiviral effects in laboratory tests, and are of interest as potential treatments against SARS-CoV-2, the current study has found that they do not benefit patients undergoing treatment for Covid-19.


"This is the first large scale study to find statistically robust evidence that treatment with chloroquine or hydroxychloroquine does not benefit patients with Covid-19," Mehra said.