What should you pay attention to when taking Tolvaptan?

During treatment with Tolvaptan tablets, patients should be aware that correcting serum sodium too quickly can lead to severe neurological sequelae, dehydration and hypovolemia, liver damage, acute urinary retention with outflow obstruction and other adverse events. Patients should also pay attention to hyperkalemia or drugs that increase serum potassium and drug interactions.

1. Correction of serum sodium too quickly can lead to severe neurological sequelae: Osmotic demyelination syndrome is a risk associated with correction of hyponatremia too quickly, which may lead to dysarthria, mutism, dysphagia, drowsiness, affective changes, spastic quadriplegia, seizures, coma, or death. A slower rate of correction may be prudent in susceptible patients, including those with severe malnutrition, alcohol abuse, or advanced liver disease.

2. Dehydration and hypovolaemia: Tolvaptan therapy causes large amounts of urination, which is usually partially offset by fluid intake. Dehydration and hypovolemia may occur, particularly in patients with underlying volume depletion receiving diuretics or in patients with fluid restriction.

3. Liver damage: Tolvaptan can cause severe and potentially fatal liver damage. In placebo-controlled studies and open-label extension studies of long-term use of tolvaptan in patients with ADPKD, severe cases of tolvaptan-induced liver injury have been observed, usually occurring during the first 18 months of treatment. In postmarketing experience with tolvaptan in the treatment of ADPKD, there have been reports of acute injury leading to liver failure requiring liver transplantation.

4. Drug interactions: Tolvaptan is a substrate of CYP3A. Moderate to severe CYP3A inhibitors can cause a significant increase in tolvaptan concentration. Do not use tolvaptan together with strong CYP3A inhibitors.

5. Hyperkalemia or drugs that increase serum potassium: Tolvaptan treatment is associated with an acute decrease in extracellular fluid volume, which may lead to an increase in serum potassium. Serum potassium levels should be monitored after initiation of tolvaptan therapy in patients with serum potassium >5 mEq/L and in patients receiving drugs known to increase serum potassium levels.

6. Acute urinary retention with outflow tract obstruction: Patients with partial obstruction of the urinary outflow tract, such as patients with prostatic hypertrophy or voiding disorders, have an increased risk of acute urinary retention. Tolvaptan should not be used in patients with uncorrected urinary outflow obstruction.

Tolvaptan tablets have been marketed in China and have entered the scope of Class B medical insurance. The price paid by medical insurance is relatively cheap, but the reimbursement ratio is different in different regions, and the price after reimbursement will be different. Domestic pharmacies or hospitals will sell this drug, and the original drug of tolvaptan tablets is also on the market overseas. There are also generic tolvaptan tablets produced in other countries. The price of Indian pharmaceutical factory production specifications15mg*4 tablets per box is around RMB 800 (the price may fluctuate due to the exchange rate). The ingredients of foreign generic drugs are basically the same as those of domestic and foreign original drugs.