Leqembi and Kisunla may lead to an infusion-related reaction which includes fever, chills, and body aches. The treatments are also linked with the risk of brain swelling and microhemorrhages, called amyloid-related imaging abnormalities (ARIA). These side effects are usually asymptomatic but may present serious health risks in rare cases. As a result, anyone undergoing treatment with these medications receives careful monitoring via regular MRI scans to spot ARIA.