Two drugs that have been proposed as a potential treatment for the new coronavirus, hydroxychloroquine and azithromycin, could be a lethal combination according to a new study. The combination could seriously impact the cardiovascular system as per researchers from Vanderbilt and Stanford University, who carried out an observational, retrospective meta-analysis of a WHO database of over 21 million case reports. The reports are dated November 1967-March 2020 across 130 countries. Reports of potentially lethal acute cardiac proarrhythmogenic effects have been described mainly with azithromycin but also with hydroxychloroquine. And together, the risk was even stronger, according to the report published in the journal Circulation.