Chloroquine diphosphate in two different dosages as adjunctive therapy of hospitalized patients with severe respiratory syndrome in the context of coronavirus (SARS-CoV-2) infection: Preliminary safety results of a randomized, double-blinded, phase IIb clinical trial (CloroCovid-19 Study)

Mayla Borba; Fernando de Almeida Val; Vanderson Sousa Sampaio; Marcia Araujo Alexandre; Gisely Cardoso Melo; Marcelo Brito; Maria Mourao; Jose Diego Brito Sousa; djane Baia-da-Silva; Marcus Vinitius Farias Guerra; Ludhmila Hajjar; Rosemary Costa Pinto; Antonio Balieiro; Felipe Gomes Naveca; Mariana Xavier; Alexandre Salomao; Andre Siqueira; Alexandre Schwarzbolt; Julio Henrique Rosa Croda; Mauricio Lacerda Nogueira; Gustavo Romero; Quique Bassat; Cor Jesus Fontes; Bernardino Albuquerque; Claudio Daniel-Ribeiro; Wuelton Monteiro; Marcus Lacerda

In two patients, myocarditis was suspected based on the CKMB elevation since the first day of hospitalization, suggesting myocarditis related to SARS-CoV-2 itself. In such cases, drugs prolonging QTc could lead to severe arrhythmias. Unfortunately, this study's randomization, probably due to the low sample size, assigned older patients with heart disease to the high dosage arm. Therefore, one limitation for the conclusions of the study on lethality per arm is that high CQ dosage arm presented more patients prone to cardiac complications, with or without CQ. In any case, the use of CQ in elderlies with heart disease should be made with caution.