Asian Journal of Research in Nephrology

Nephrogenic Diabetes Insipidus (NDI) is a rare but serious renal complication of long-term lithium therapy, characterized by renal resistance to Anti-Diuretic Hormone (ADH), leading to persistent polyuria and polydipsia. If unrecognized, it can cause severe dehydration and electrolyte imbalances. Sodium valproate, the other mood stabilizer in widespread use, is reported to cause transient central diabetes insipidus in cases of drug overdose. However, NDI due to sodium valproate is not reported in the literature. Here we present a 64-year-old male on prolonged valproate therapy who developed polyuria and polydipsia. Further evaluation confirmed NDI after a water deprivation and desmopressin challenge test. His condition improved after valproate discontinuation and hydrochlorothiazide initiation. This case highlights a very rare complication of prolonged valproate therapy which is not reported so far. Hence, clinicians should maintain a high index of suspicion in long-term valproate users so that timely intervention to avoid further complications can be employed.