Class: Vasopressin Antagonist
Dosage Forms. Tablet: 15 mg, 30 mg
Common FDA Label Indication, Dosing, and Titration.
1. Hypervolemic or euvolemic hyponatremia: 15 mg po daily, may titrate to max of 60 mg po daily
1. Heart failure: 15 mg po daily, may titrate to max of 60 mg po daily
MOA. Tolvaptan is a selective vasopressin V2-receptor antagonist with an affinity for the V2-receptor that is 1.8 times that of native arginine vasopressin (AVP). When taken orally, tolvaptan antagonizes the effect of vasopressin and cause an increase in urine water excretion that results in an increase in free water clearance, a decrease in urine osmolality, and a resulting increase in serum sodium concentrations.
Drug Characteristics: Tolvaptan
Medication Safety Issues: Tolvaptan
Drug Interactions: Tolvaptan
Adverse Reactions: Tolvaptan
Efficacy Monitoring Parameters. Monitor serum sodium levels carefully; normalization of serum sodium is the efficacy parameter.
Toxicity Monitoring Parameters. Monitor for dehydration, serum electrolytes, neurologic status, signs and symptoms of syndrome of inappropriate antidiuretic hormone secretion. Monitor LFTs and discontinue if increased.
Key Patient Counseling Points. May be taken with or without food. Avoid fluid restriction for the first 24 h of therapy. Resume fluid restriction on discontinuation.
Clinical Pearls. Initiate and reinitiate therapy only in the hospital setting, monitoring serum sodium carefully. Should not be used for >30 d in patients with underlying liver disease.