The early results of this study suggest that higher chloroquine doses should not be recommended for critically ill patients with COVID-19 because of potential safety hazards, especially if combined with azithromycin and oseltamivir.

In this parallel, double-masked, randomized clinical trial of 81 adult patients hospitalized with COVID-19, researchers sought to evaluate the safety and efficacy of 2 chloroquine dosages in patients. They were allocated to get high-dosage chloroquine (600 mg twice daily for 10 days) or low-dosage chloroquine (450 mg twice daily on day 1 and once daily for 4 days).

The patients had a mean age of 51 years, and 75% were men. Older age and more heart disease were seen in the high-dose group. Viral RNA was detected in 78% and 76% patients in the low-dose and high-dose groups, respectively.

Lethality until day 13 was 39% in the high-dose group and 15.0% in the low-dose group. The high-dose group had more long QT issues (19%) compared to the low-dose group (11%).