Abnormalities of the esophagus which delay esophageal emptying such as stricture or achalasia; Inability to stand or sit upright for at least 30 minutes; Hypersensitivity to any component of this product; Hypocalcemia (see PRECAUTIONS); Renal insufficiency with creatinine clearance <0.58 mL/s (<35 mL/min) (see DOSAGE & ADMINISTRATION).