A Multicenter Trial to Investigate the Efficacy and Safety of Tolvaptan in Patients With Hyponatremia in SIADH

A Multicenter, Uncontrolled, Open-label, Dose-titration Trial to Investigate the Efficacy and Safety of Tolvaptan Tablets in Patients With Hyponatremia in Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)

The objective of this study is to investigate the efficacy and safety of tolvaptan based on the change in serum sodium concentration following administration of tolvaptan oral tablets at 7.5 to 60 mg/day for up to 30 days in patients with hyponatremia in the SIADH.

Inclusion Criteria:

• Subjects with a definite diagnosis of SIADH in reference to "Diagnostic and Treatment Manual of the Hypersecretion of Vasopressin (SIADH), Revised in 2011"
• Subjects who have been on fluid restriction for at least 7 consecutive days at the time of informed consent and who are showing no improvement of hyponatremia at the time of the screening examination

Exclusion Criteria:

• Subjects who have transient hyponatremia induced by drug administration
• Subjects who are unable to sense thirst or who have difficulty with fluid intake
• Subjects with urinary tract obstruction
• Subjects who have participated in any other clinical trial within 30 days prior to informed consent
• Subjects with serum sodium concentration of <120 mEq/L associated with neurologic impairment, including apathy, confusion, or seizures