The following assessments are required within 2 weeks prior to the start of registration: sodium (Na), potassium (K), chloride (Cl), glucose, calcium (Ca), magnesium (Mg), and albumin; note: patients with an initial magnesium < 0.5 mmol/L (1.2 mg/dl) may receive corrective magnesium supplementation but should continue to receive either prophylactic weekly infusion of magnesium and/or oral magnesium supplementation (e.g., magnesium oxide) at the investigators discretion Serum phosphorus calcium, magnesium and potassium >= lower limit of normal (LLN) Serum calcium and magnesium above the institutional lower limit of normal, within 14 days of registration and within 7 days of the start of treatment The following assessments are required within 14 days prior to registration: sodium (Na), potassium (K), chloride (Cl), glucose, calcium (Ca), magnesium (Mg), and albumin; Note: patients with an initial magnesium < 0.5 mmol/L (1.2 mg/dl) may receive corrective magnesium supplementation but should continue to receive either prophylactic weekly infusion of magnesium and/or oral magnesium supplementation (e.g., magnesium oxide) at the investigators discretion Serum phosphorus >= lower limit of normal (LLN) Calcium >= LLN Magnesium >= LLN Potassium >= LLN Serum phosphorus, calcium, magnesium and potassium >= lower limit of normal (LLN) Magnesium > 1.2 and < 2.5 mEq Serum phosphorus >= lower limit of normal (LLN) Serum calcium >= LLN Serum magnesium >= LLN Serum potassium >= LLN Serum phosphorus >= lower limit of normal (LLN) (if below LLN, for asymptomatic patients replacement may be initiated if clinically indicated without delaying the start of study treatment) Serum calcium >= LLN (if below LLN, for asymptomatic patients replacement may be initiated if clinically indicated without delaying the start of study treatment) Serum magnesium >= LLN (if below LLN, for asymptomatic patients replacement may be initiated if clinically indicated without delaying the start of study treatment) Serum potassium >= LLN (if below LLN, for asymptomatic patients replacement may be initiated if clinically indicated without delaying the start of study treatment) Potassium above the institutional lower limit of normal (supplementation to meet this is allowed) Magnesium above the institutional lower limit of normal (supplementation to meet this is allowed) Serum potassium, magnesium, and calcium levels within 28 days before randomization must be within normal limits (WNL) for the lab within 28 days before randomization The following assessments are required within 14 days prior to registration: sodium (Na), potassium (K), chlorine (Cl), glucose, calcium (Ca), magnesium (Mg), and albumin; note: patients with an initial magnesium < 0.5 mmol/L (1.2 mg/dl) may receive corrective magnesium supplementation but should continue to receive either prophylactic weekly infusion of magnesium and/or oral magnesium supplementation (e.g., magnesium oxide) at the investigators discretion Sodium >= the institutional lower limit of normal