FRANKFURT - The European Union's drug regulator warned again on Thursday against using two older malaria drugs to treat COVID-19, caused by the novel coronavirus, outside trials or national emergency use programs, citing potentially lethal side-effects.
The European Medicines Agency (EMA) urged medical professionals to closely monitor COVID-19 patients receiving chloroquine or hydroxychloroquine and "carefully consider the possibility of side effects, particularly with higher doses". Extra caution was warranted if either were used with other drugs.
The two drugs potentially cause irregular heartbeat, a condition that could be worsened when used in combination with other medicines such as the antibiotic azithromycin.
Decades-old hydroxychloroquine has been widely used, particularly in the United States, to try to alter the course of the respiratory illness COVID-19, based on anecdotal reports that it may provide some benefit.
US President Donald Trump has touted hydroxychloroquine as a "game-changer" in the fight against the new coronavirus, which has claimed nearly 184,000 lives worldwide.
But an analysis of US Veterans Health Administration data submitted for expert review showed that hydroxychloroquine provided no benefit and potentially higher risk of death for patients at US veterans hospitals.
On Thursday, EMA said a number of large trials were investigating the drugs as COVID-19 treatments but data has been inconclusive and no benefits had been demonstrated so far.
It said the two drugs -- approved to treat malaria, lupus and rheumatoid arthritis -- were known to potentially cause liver and kidney problems, nerve cell damage and low blood sugar levels.