Hydroxychloroquine: NHS staff to take drug as part of global trial

Chloroquine and hydroxychloroquine have been used for treating malaria for more than 60 years and are generally regarded as very safe drugs. Until recently 300m chloroquine treatments were given for malaria every year – it is less used now because of resistance and the development of artemisinin drugs.

Side-effects are usually mild and include stomach upset and nausea, headache and temporary blurring of vision, but too high a dose can be dangerous and lead to death. There is concern that the drugs can prolong the electrocardiogram QT interval, causing an irregular heart rhythm. People who already take other drugs that could cause this side-effect should be careful, say the scientists on their trial website, “but for healthy people who are not taking regular medications which prolong the QT interval, there should be no concerns about cardiotoxicity”.