Tolvaptan for Hyponatremia in Advanced CKD

Background: Hyponatremia is a common problem in patients with chronic kidney disease(CKD). Tolvaptan has been used for the treatment of hyponatremia. But there is a paucity of literature about its use in stage 4 and stage 5 CKD. There are reports on its use in CKD for heart failure. Therefore, we conducted this observational study to assess the efficacy of tolvaptan in advanced CKD. Methods: There were 46 subjects in the study. All patients were with stage 4and 5 CKD. We included patients with serum sodium<118 meq/I. Patients with symptomatic hyponatremia were included. Patients who needed renal replacement therapy were excluded. Patients who needed hypertonic saline due to seizures or coma were excluded. Their basic demographic data was recoded. They were observed with daily serum sodium, urine output, urine osmolality, and clinical examination. We used t-test to compare the data between 2 groups Results: We used tolvaptan in 46 patients of stage 4 and 5 CKD. They had a mean e GFR of 14.8±1.7 ml/minute. They had a mean age of 41±5.7 years. Gender ratio was 14:9(male: female). Causes of renal failure were diabetic nephropathy (n=18), Hypertension (n=13), Chronic glomerulonephritis(n=7), Chronic interstitial nephritis(n=5) and unknown(n=3). All patients were symptomatic in the form of nausea, hiccups, and behavioral changes. They had a mean serum creatinine of 3.6±1.5mg%. Their mean serum sodium was 115.5±3.2 meq/l. They were started on tolvaptan 15 mg daily. The dosage of tolvaptan was increased to 15 mg twice a day after 2 days if the patient needed dose escalation according to clinical condition. They had a significant rise in serum sodium to a mean serum sodium of 121.6±2.1mg% on day 3. They achieved a serum sodium concentration of 128.7±3.4mg% by day 7. They did not show any significant change in serum creatinine level at day seven, which was 5.6±1.7mg%. Their mean urine volume increased from 1343±138 ml to 1588±142 ml daily (p<.05). Their mean urine osmolality also decreased from 279.6±10.9 mOsm/Kg to 239.8 mOsm/kg at day 2 and 224.5±11.9 mOsm /kg at day 4. Patients showed symptomatic improvement as well. No patient needed the withdrawal of the drug. No patient developed clinical features suggestive of osmotic demyelination syndrome. Conclusion: Tolvaptan appears safe and efficacious in advanced CKD for the management of hyponatremia.