A person walks out a pharmacy on March 24, 2020, in Paris, during a lockdown aimed at curbing the spread of the COVID-19 (novel coronavirus) in France. Pharmacies in the country have witnessed a surge in demand for hydroxychloroquine, marketed by pharmaceutical giant Sanofi under the trade name Plaquénil.

France's drug safety agency warned on Monday of potentially serious side effects of treatments being tested against the new coronavirus after the deaths of three people possibly linked to self-medication.

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Another two dozen patients have reported undesirable side effects after taking Plaquenil – the brand name of hydroxychloroquine – as well as other medicines such as the antiretroviral Kaletra, the agency's head Dominique Martin told AFP.

He said experts were trying to determine whether the drugs were linked to the side effects, with initial conclusions expected by the end of the week.

The drug safety agency (ANSM) began boosting its surveillance two weeks ago of trials of drugs against COVID-19, "in particular when they are used outside of clinical trials of chloroquine, hydroxychloroquine, azithromycin, lopinavir/ritonavir (Kaletra), tocilizumab (and) colchicine," Martin said.

"It's perfectly normal that treatments be tried, given the circumstances, but that doesn't mean we shouldn't observe surveillance... of these substances," Martin said.

Hydroxychloroquine, and its related compound chloroquine, have been the focus of intense debate in France since a study conducted on a small number of COVID-19 patients in the southern city of Marseille yielded promising results.

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On March 16, Professor Didier Raoult, the head of a university hospital institute in Marseille, announced his teams had treated 25 patients with hydroxychloroquine. After six days, he said, only one in four still had the virus in their body, whereas 90 percent of patients who had not taken the drug were still infected.

Raoult’s subsequent calls to expand the treatment, which garnered ample media attention, triggered a rush on French pharmacies – even as medical experts stressed the importance of first carrying out further trials on larger patient samples.

Combining hydroxychloroquine with the antibiotic azithromycin has been in the spotlight since Raoult published two studies that he said showed the treatment's effectiveness against COVID-19.

The treatment needs "particular attention", Martin said, because combining hydroxychloroquine with the antibiotic azithromycin, as in the Marseille trial, could cause arrhythmia and lead to a heart attack.

This was "even more the case with patients suffering from COVID-19" because of metabolic problems associated with the disease, he said.

(FRANCE 24 with AFP)

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