Overview

The purpose of this research is to study the effectiveness and safety of the medication PB in slowing the frequent urination related to tolvaptan as long-term treatment of Autosomal Dominant Polycystic Kidney Disease (ADPKD), or frequent urination related to inherited nephrogenic diabetes insipidus as an inherited condition or as an acquired condition from prior treatment with lithium.

Eligibility

Inclusion Criteria:

• Diagnosis of nephrogenic diabetes insipidus (NDI) (congenital, tolvaptan-induced, or lithium-induced).
• Morning Uosm < 300 mOsm/kg H2O.
• Participating in tolvaptan arm.
• Males for NDI.
• Autosomal Dominant Polycystic Kidney Disease (ADPKD).
• Lithium-induced NDI.
• GFR (Glomerular filtration rate) ≥ 30 ml/min.
• If hypertensive, blood pressure controlled on antihypertensives (< 130/80 mm Hg) at least 30 days before day 1.
• Capable of providing consent.
• Capable of providing urine samples as dictated by the protocol.

Exclusion Criteria:

• History of acute gout attack in the past 30 days.
• Uncontrolled hyperuricemia or active gout.
• Known urinary retention, urinary incontinence or bladder dysfunction.
• Other significant chronic medical disease (heart failure, diabetes mellitus, liver disease, transient or persistent elevated transaminases.
• History of hepatotoxicity related to tolvaptan.
• Allergy to interventional drug (PB).
• History of persistent hyponatremia.