Identifying optimal magnesium replenishment points based on risk of severe hypomagnesemia in colorectal cancer patients treated with cetuximab or panitumumab.

To minimize the risk of severe hypomagnesemia during anti-EGFR treatment, magnesium replenishment should be initiated in patients with pre-replenishment concentrations of < 1.8 mg/dL, preferably before reaching intra-treatment concentrations of < 1.1 mg/dL.