Methemoglobinemia and acute hemolysis induced by high intravenous doses of vitamin C in a COVID-19 patient with unrecognized glucose-6- phosphate-dehydrogenase deficiency

Abstract

In glucose-6-phosphate-dehydrogenase deficiency (favism), exposure to oxidant agents can trigger hemolytic crises. The intravenous administration of very high doses of vitamin C was proposed as a treatment for severe coronavirus disease 2019 (COVID-19) pneumonia. Unlike low vitamin C doses, very high doses (>6 gr daily) can promote H2O2 formation, oxidation of hemoglobin to methemoglobin and, eventually, hemolytic anemia in patients with favism. We here describe the case of a 77-year old man hospitalized for severe COVID-19 pneumonia and treated with a mean daily dose of 9.5 gr of intravenous vitamin C during the first 6 days. He developed methemoglobinemia and hemolytic anemia, which improved after interruption of vitamin C treatment. Previously unrecognized glucose- 6-phophate-dehydrogenase deficiency was diagnosed. This first case of vitamin Cinduced hemolytic anemia in a COVID-19 patient indicates the need of a screening for glucose-6-phosphate-dehydrogenase deficiency before treatment with very high vitamin C doses or for long period.