Rasburicase-induced methemoglobinemia and haemolytic anaemia in a patient with G6PD deficiency

Rasburicase is a recombinant urate oxidase enzyme indicated in patients at a high risk of tumour lysis syndrome. Rasburicase is contraindicated in patients with glucose-6-phosphate-dehydrogenase (G6PD) deficiency, given the risk of precipitating oxidative stress, haemolytic anaemia, as well as methemoglobinemia. We present a case of a man in his 40s without risk factors for G6PD deficiency, who after rasburicase administration developed severe haemolytic anaemia and hypoxia. Although studies validating the use of rasburicase were at a dosage of 0.2 mg/kg up to 5 days, there are new studies suggesting a lower dose such as 3 mg be just as efficacious in normalising uric acid. There is no evidence to date suggesting higher risk of haemolytic anaemia with increased dosage of rasburicase, but this case highlights the need to assess on a broader level whether 3 mg as a one-time dose should be the new standard of care or whether lower dosages are safer for patients.