Preclinical and clinical data on chloroquine (CQ) and hydroxychloroquine (HCQ) in coronavirus disease 2019 (Covid-19)
| Type of study | Main results | |
| Wang et al 1 | In vitro | At low micromolar concentration, CQ blocks viral infection at both entry and at post-entry stages of the 2019-nCoV infection in Vero E6 cells. |
| Yao et al 2 | In vitro | HCQ is more potent than CQ in inhibiting viral infection at entry and post-entry stages; EC50 values CQ and HCQ decreased with longer incubation times providing higher intracellular concentrations and a better antiviral effect. Suggested dosing for HCQ: 400 mg/two times a day at day 1, followed by 200 mg/two times a day. |
| Gao et al 3 | Case series | CQ phosphate is superior to the control treatment in inhibiting the exacerbation of pneumonia, improving lung imaging findings, promoting a virus-negative conversion and shortening the disease course. No severe adverse events were reported. |
| Gautret et al 4 | Case control | HCQ induces viral clearance after 6 days of treatment, either alone or in combination with azithromycin (respectively, 70% and 100% negative nasopharyngeal samples among treated patients compared with 12.5% of untreated patients). |
EC, effective concentration 50; nCoV, novel coronavirus.