Table 1

QTc prolongation and ventricular arrhythmia or mortality in trials using hydroxychloroquine (HCQ) or chloroquine (CQ) in combination with azithromycin (AZT)

StudyDrugDoseStudy sizeOutcomes
Van den Broek et al28CQ alone600 mg loading dose then 300 mg BD for 5 days95

  • QTc prolonged from 444 ms to 479 ms (p<0.01)

  • QTc >500 ms in 22 patients (23.2%)

  • No ventricular arrhythmias

Borba et al11High-dose CQ+AZT
Low-dose CQ+AZT		600 mg BD for 10 days or
450 mg BD for 1 day then 450 mg BD for 4 days		81

  • Increased mortality rates in high-dose group (39.0% vs 15.0%)

  • Increased rate of QTc >500 ms in high-dose group (18.9% vs 11.1%)

  • Ventricular arrhythmia in 2 patients (2.7%)

Chorin et al27HCQ+AZT400 mg BD for 1 day then 200 mg BD for 4 days84

  • QTc prolonged from 435 ms to 463 ms (p<0.001)

  • QTc >500 ms in 9 patients (11%)

Saleh et al31HCQ or CQ alone
HCQ/CQ+AZT		HCQ: 400 mg BD for 1 day then 200 mg BD for 4 days
CQ: 500 mg BD for 1 day then 500 mg OD for 4 days		201

  • Combination therapy associated with increased QTc prolongation (470.4±45.0 ms vs 453.3±37.0 ms, p=0.004)

  • Ventricular arrhythmia in 8 patients (4.0%)

  • 7 patients (3.5%) discontinued due to QTc prolongation

Mercuro et al29HCQ alone
HCQ+AZT		400 mg BD for 1 day then 400 mg OD for 4 days90

  • Combination therapy associated with increased QTc prolongation (23 ms vs 5.5 ms; p=0.03)

  • QTc >500 ms in 18 patients (20%)

  • 1 episode of TdP

  • 10 patients (11%) discontinued due to QTc prolongation

Bessière et al26HCQ alone
HCQ+AZT		200 mg BD for 10 days40

  • QTc prolonged from 414 ms to 454 ms (p<0.01)

  • QTc >500 ms in 7 patients (17.5%)

  • No ventricular arrhythmias

  • 7 patients (17.5%) discontinued due to QTc prolongation

Mahévas et al30HCQ alone600 mg daily181

  • No mortality benefit of HCQ+AZT group vs no HC (10.7% vs 9.0%; HR 1.2 (0.5 to 3.0))

  • 8 patients (10%) discontinued due to QTc prolongation

Magagnoli et al12HCQ alone
HCQ+AZT		Details not reported368

  • Increased mortality rates in HCQ group vs no HCQ (27.8% vs 11.4%; p=0.03)

  • No mortality benefit of HCQ+AZT group vs no HCQ (22.1% vs 11.4%; p=0.72)

Geleris et al3HCQ alone600 mg BD for 1 day then 400 mg OD for 4 days1376

  • Outcome of intubation/death unchanged with HCQ (HR 1.04 (0.82 to 1.32))

  • BD, twice daily; OD, once daily; TdP, torsades de pointes.