From the FDA Drug Label
5.1 Hyponatremia Clinically significant hyponatremia (sodium <125 mmol/L) can develop during oxcarbazepine use. In the 14 controlled epilepsy studies 2. 5% of oxcarbazepine-treated patients (38/1,524) had a sodium of less than 125 mmol/L at some point during treatment, compared to no such patients assigned placebo or active control 2.5% of patients developed hyponatremia (sodium <125 mmol/L) during treatment with oxcarbazepine, as reported in the 14 controlled epilepsy studies 1.
From the Research
Approximately 61.3% of patients taking oxcarbazepine develop hyponatremia, with 19.4% experiencing severe hyponatremia, according to the most recent study 2. The risk of hyponatremia is significantly higher in patients taking oxcarbazepine compared to other anti-seizure medications, with a mean serum sodium concentration of 133.1 ± 5.1 mmol/L in the oxcarbazepine group 2. The frequency of hyponatremia among oxcarbazepine-treated patients is significantly higher compared to other groups, with a significant negative correlation between serum sodium concentration and duration of treatment with oxcarbazepine 2. Key factors that increase the risk of hyponatremia in patients taking oxcarbazepine include:
- Longer duration of treatment with oxcarbazepine, with each year of therapy increasing the risk of hyponatremia 1.3 times (OR = 1.326,95% CI 1.027-1.712, p = 0.031) 2
- Advanced age, with older patients being more likely to experience severe hyponatremia 2, 3
- Combination with other drugs, particularly those that affect sodium levels, such as diuretics 4, 5 Monitoring sodium levels is crucial in patients taking oxcarbazepine, especially in high-risk patients, to detect hyponatremia early and prevent further complications. Symptoms of hyponatremia include headache, confusion, nausea, and in severe cases, seizures or coma, and management may involve dose reduction, discontinuation of the medication, or fluid restriction depending on severity 4, 5.