Samsca Generic Name & Formulations
Tolvaptan 15mg, 30mg; tabs.
Selective vasopressin V2-receptor antagonist.
Clinically significant euvolemic and hypervolemic hyponatremia (serum sodium <125mEq/L or less marked hyponatremia that is symptomatic and has resisted correction with fluid restriction), including patients with heart failure and syndrome of inappropriate antidiuretic hormone (SIADH).
Limitations of Use
Not for urgent serum sodium correction to prevent or treat serious neurological symptoms.
Samsca Dosage and Administration
Initiate and re-initiate only in a hospital. Initially 15mg once daily, may increase dose after ≥24hrs to 30mg once daily, then to max 60mg once daily as needed to raise serum sodium. Max therapy: 30 days duration. Avoid fluid restriction during the first 24hrs of therapy; resume fluid restriction after drug discontinuation.
Autosomal dominant polycystic kidney disease (ADPKD). Unable to sense or respond to thirst. Hypovolemic hyponatremia. Concomitant strong CYP3A inhibitors (eg, clarithromycin, telithromycin, ketoconazole, itraconazole, ritonavir, indinavir, nelfinavir, saquinavir, nefazodone). Anuria.
Samsca Boxed Warnings
Initiate and re-initiate in a hospital and monitor serum sodium. Not for use for ADPKD.
Do not use for ADPKD outside of FDA-approved REMS; risk of serious and potentially fatal liver injury. Risk of osmotic demyelination syndrome; discontinue or interrupt therapy if too rapid a rise in serum sodium occurs (eg, >12mEq/L/24hrs). Severe malnutrition, alcoholism, or advanced liver disease: slower rates of correction advisable. Patients with SIADH or low baseline serum sodium concentrations. Avoid in patients with underlying liver disease, including cirrhosis; discontinue if symptoms of liver injury develop. Severe renal impairment (CrCl<10mL/min): not recommended. Monitor frequently for changes in serum sodium, volume and neurologic status during initiation and titration. Monitor serum potassium in patients with K+ >5mEq/L after initiation. Uncorrected urinary outflow obstruction. Pregnancy. Nursing mothers: not recommended.
See Contraindications. Potentiated by CYP3A inhibitors, grapefruit juice; avoid moderate CYP3A inhibitors (eg, fluconazole). Antagonized by CYP3A inducers (eg, rifampin); avoid concomitant use. Potentiates digoxin. Concomitant hypertonic saline or V2 agonist (desmopressin): not recommended. Concomitant diuretics increases the risk of too rapid correction of sodium; monitor serum sodium closely. Hyperkalemia with ARBs, ACEIs, K+-sparing diuretics; monitor serum K+.
Samsca Adverse Reactions
Thirst, dry mouth, asthenia, constipation, pollakiuria, polyuria, hyperglycemia; osmotic demyelination syndrome, liver injury, hypovolemia (discontinue or interrupt if significant), hyperkalemia.
Samsca Clinical Trials
Samsca Patient Counseling