Paris, March 31 : French health authorities have issued a warning about the anti-malarial drug hydroxychloroquine and other medications being used to treat patients infected with the novel coronavirus, saying around 30 people who had been administered these medicines suffered severe side-effects. "We remind you that no medication has been formally shown to be effective in treating or preventing the COVID-19 disease. For this reason, plaquenil (hydroxychloroquine) or kaletra and its generic equivalents (lopinavir and ritonavir) should only be used as part of ongoing clinical trials," France's National Agency for the Safety of Medicines and Health Products (ANSM) said on Monday. The Agency said in no case may these drugs be auto-administered at home nor prescribed by doctors outside of the hospital setting, as French right-wing populist leader Marine Le Pen demanded on Monday, reports Efe news. After regional pharmacovigilance centres in France observed that these drugs were being misused, the ANSM decided to alert patients and doctors about side-effects such as dangerous heart problems that may require hospitalization. "This cardiac risk could be greatly potentiated by the use of hydroxychloroquine in combination with other molecules, such as azithromycin, as well as due to the metabolic disorders specific to Covid-19 (hypokalemia)," it said. In that regard, the ANSM added that there had been several instances of serious side effects that are now being analyzed. Last week, French health authorities permitted the use of the anti-malarial drug chloroquine to treat COVID-19 patients who are in serious condition and under strict medical supervision. It made that decision after an infectious disease expert and head of a university hospital institute in the southern French city of Marseille, Didier Raoult, said he had treated 24 coronavirus patients with hydroxychloroquine (a derivative of chloroquine) and the antibiotic azithromycin and obtained promising results. The French government has said that the efficacy of hydroxychloroquine is being tested in clinical trials but that its alleged success in treating the novel coronavirus has not yet been verified. On Sunday, the US Department of Health and Human Services (HHS) issued a statement noting that the US Food and Drug Administration (FDA) had given authorization for hydroxychloroquine and chloroquine to be used to treat hospitalized patients. The FDA has issued an Emergency Use Authorization to the HHS's Biomedical Advanced Research and Development Authority "to allow hydroxychloroquine sulfate and chloroquine phosphate products donated to the Strategic National Stockpile (SNS) to be distributed and prescribed by doctors to hospitalized teen and adult patients with COVID-19, as appropriate, when a clinical trial is not available or feasible". /IANS