Drug General Information (ID: DDI28VFIA4)
Drug Name			Sodium bicarbonate		Drug Info		Tolvaptan		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antidiarrheals				Vasopressin Antagonists
Structure

Mechanism of Sodium bicarbonate-Tolvaptan Interaction (Severity Level: Moderate)
Increased risk of hypernatremia Click to Show/Hide Mechanism Graph
Drug Name		Sodium bicarbonate				Tolvaptan
Mechanism		Hypernatremia				Hypernatremia
Key Mechanism Factor 1
		Factor Name		Hypernatremia
		Factor Description		Hypernatremia is defined as a serum sodium concentration >145 mEq/L (>145 mmol/L). It implies a deficiency in total body water due to less water intake than water loss relative to total body sodium. The main symptom is thirst; other clinical manifestations are mainly neurological (due to osmotic transfer of water from brain cells) and include confusion, neuromuscular excitability, seizures and coma.
Mechanism Description		Increased risk of hypernatremia by the combination of Sodium bicarbonate and Tolvaptan

Recommended Action
Management		The concomitant use of tolvaptan with hypertonic saline is not recommended. Caution and monitoring are recommended for patients who have received other medications that increase serum sodium levels.

References
1	Cerner Multum, Inc. "UK Summary of Product Characteristics.".
2	Product Information. Samsca (tolvaptan). Otsuka American Pharmaceuticals Inc, Rockville, MD.
3	Canadian Pharmacists Association.