Ruibeitan Tolvaptan Tablets

1. Indications and Usage
Hyponatremia: Treatment of clinically significant hypervolemic and euvolemic hyponatremia (serum sodium <125 mEq/L, or not severe but symptomatic and unresponsive to fluid restriction), including patients with heart failure, cirrhosis, and syndrome of inappropriate antidiuretic hormone secretion (SIADH).
Fluid Overload in Heart Failure: Treatment of fluid overload in heart failure when other diuretics are ineffective.
Usage Restrictions: Not indicated for urgent elevation of serum sodium to prevent or treat severe neurological symptoms.
2. Dosage and Administration
Route of Administration: Oral administration.
Standard Dosage: The usual starting dose is 15 mg once daily. The dose may be increased to 30 mg or 60 mg once daily after at least 24 hours to raise serum sodium concentration.
Critical Administration Instructions:
Food: Can be taken with or without food.
Hydration: Avoid restricting fluid intake during the first 24 hours of treatment unless monitored. Patients should drink fluids when thirsty.
Duration: To reduce the risk of liver injury, treatment should generally not exceed 30 days.
3. Mechanism of Action
V2 Receptor Antagonism: Tolvaptan selectively blocks the vasopressin V2 receptors in the renal collecting ducts.
Aquaresis: This inhibition prevents the reabsorption of free water into the bloodstream, increasing free water clearance (aquaresis) and gradually normalizing serum sodium levels without significant loss of electrolytes.
4. Safety and Warnings
Hepatotoxicity: May cause serious and potentially fatal liver injury. Liver enzymes must be monitored regularly, especially in patients with autosomal dominant polycystic kidney disease (ADPKD).
Overly Rapid Correction of Hyponatremia: Rapidly raising serum sodium can cause osmotic demyelination syndrome, leading to severe neurological damage.
Hypovolemia and Hypernatremia: Aggressive diuresis can lead to excessive fluid loss, hypovolemia, and hypernatremia.
Contraindications: Contraindicated in anuric patients, hypovolemic hyponatremia, patients unable to perceive thirst, and those taking strong CYP3A inhibitors (e.g., ketoconazole).
5. Adverse Reactions and Clinical Research
Most Common Adverse Reactions: Thirst, dry mouth, polyuria, and nausea.
Clinical Research Highlights: Clinical trials have demonstrated significant and rapid correction of serum sodium levels and effective reduction of fluid overload in heart failure patients.
6. Drug Interactions
Strong CYP3A Inhibitors: Concomitant use with agents like ketoconazole significantly increases tolvaptan exposure and is contraindicated.
Moderate CYP3A Inhibitors: Use should be avoided due to increased exposure.
Strong CYP3A Inducers: Agents like rifampin may decrease tolvaptan efficacy.
Other Diuretics: Can be combined with loop or thiazide diuretics, but requires careful monitoring of volume status and electrolytes.
7. Pharmaceutical Information
Chemical Composition: Active Ingredient: Tolvaptan.
Appearance: Blue tablets.
Packaging: Blister packs.
Storage: Store at controlled room temperature, protected from light and moisture.