- Patients younger than 18 years, participants from other studies, pregnant women, patients with admission plasma creatinine greater than or equal to 3.5 mg / dl or on dialysis, patients who used intravenous contrast for radiological studies, patients weighing less than 40kg, patients suffering from advanced cancer, patients with severe hypomagnesemia (serum magnesium less than or equal to 1.1 mg / dl), patients with a diagnosis of Torsades de Pointes or patients with symptomatic hypomagnesemia prior to randomization.