Tolvaptan
Samsca (tolvaptan) is a vasopressin V2 receptor antagonist used to treat hyponatremia (low blood sodium) in patients with heart failure, cirrhosis, and syndrome of inappropriate antidiuretic hormone secretion (SIADH). It works by blocking the action of antidiuretic hormone, allowing the kidneys to excrete excess water while retaining sodium, thereby helping to normalize sodium levels in the blood.
Samsca is a medication used to treat low blood sodium by helping the body excrete excess water while retaining sodium.
Key facts at a glance
- RxNorm
- 849828
- Generic
- Samsca
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Treatment of clinically significant hypervolemic or euvolemic hyponatremia (low blood sodium) associated with heart failure, liver cirrhosis, and SIADH. Not indicated for the treatment of autosomal dominant polycystic kidney disease (ADPKD) in this formulation context.
Samsca is a selective vasopressin V2 receptor antagonist. It blocks vasopressin from acting on the collecting ducts of the kidneys, preventing water reabsorption. This leads to increased water excretion (aquaresis) while sodium is retained, resulting in correction of low serum sodium levels.
Must be initiated in a hospital setting with close monitoring of serum sodium. Patients should be able to respond to thirst. Not for use in patients who are anuric or have urgent need to raise sodium. Avoid in patients with hypovolemic hyponatremia. Can cause liver injury; liver function should be monitored. Common side effects include thirst, dry mouth, increased urination, and hypernatremia.
Official drug label
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This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy