A call to caution when hydroxychloroquine is given to elderly COVID-19 patients.

INTRODUCTION: Hydroxychloroquine use in COVID-19 patients was widespread and uncontrolled until recently. Patients vulnerable to severe COVID-19 are at risk for hydroxychloroquine interactions with comorbidities and co-medications contributing to detrimental, including fatal adverse treatment effects. METHODS: This is a retrospective survey of health conditions and co-medications of COVID-19 patients who were pre-screened for enrolment into a randomized, double-blind, placebo-controlled hydroxychloroquine multicenter trial. RESULTS: Our survey involved 305 patients (median age 71 (IQR: 59-81) years). The majority of patients (N = 279, 92%) considered for inclusion into the clinical trial were not eligible mainly due to safety concerns caused by health conditions or co-medications. Most common were QT prolonging drugs (N = 188, 62%) and hematologic/hemato-oncologic diseases (N = 39, 13%) which prohibited the administration of hydroxychloroquine in our clinical trial. Additionally, 165 (54%) patients had health conditions and 167 (55%) were on co-medications that did not prohibit hydroxychloroquine treatment but had a risk of adverse interactions with hydroxychloroquine. Most common were diabetes (N = 86, 28%), renal insufficiency (N = 69, 23%) and heart failure (N = 58, 19%). CONCLUSION: The majority of hospitalized COVID-19 patients had health conditions or took co-medications precluding safe treatment with hydroxychloroquine. Therefore, especially in elderly, hydroxychloroquine should be administered with extreme caution and only in clinical trials