Clinical information
Common uses
- low blood sodium (hyponatremia)
- hyponatremia in heart failure or SIADH
Common side effects
- thirst
- dry mouth
- weakness
- constipation
- peeing more often or in large amounts
Cautions
- started and restarted only in hospital with sodium monitoring
- raising sodium too fast can cause serious brain injury
- not for polycystic kidney disease — liver injury risk
- limit treatment to 30 days; avoid with liver disease
Interactions
- strong CYP3A inhibitors — do not use
- moderate CYP3A inhibitors — avoid
- strong CYP3A inducers — avoid
- other V2-receptor antagonists — avoid
- ACE inhibitors, ARBs, potassium-sparing diuretics — monitor potassium
Pregnancy: may harm an unborn baby — avoid
Reference information, not medical advice — always follow your doctor or pharmacist. Source: DailyMed, dailymed.nlm.nih.gov, tolvaptan (Samsca) label, setid 5526617c-c7b9-4556-886d-729bbabbc566 (accessed 2026-08-16)