( 7.2 ) 7.1 Effect of Other Drugs on XOFLUZA Baloxavir may form a chelate with polyvalent cations such as calcium, aluminum, or magnesium. Coadministration with polyvalent cation-containing products may decrease plasma concentrations of baloxavir [see Clinical Pharmacology (12.3) ], which may reduce XOFLUZA efficacy.
Source: FDA drug label - baloxavir marboxil