From the Research
Lamotrigine can cause hyponatremia, and patients taking this medication should be closely monitored for symptoms of low sodium levels, particularly those with risk factors such as elderly patients, those on other medications that can lower sodium, and patients with conditions predisposing them to electrolyte imbalances. The risk of hyponatremia associated with lamotrigine is highlighted in a case report from 1, where a 35-year-old woman died due to lack of recognition of SIADH triggered by the use of lamotrigine and paliperidone. This case emphasizes the importance of paying sufficient attention to symptoms that may cause this syndrome and their early recognition to save lives.
Key Considerations
- Patients taking lamotrigine should be monitored for symptoms of hyponatremia such as headache, confusion, nausea, fatigue, muscle weakness, and in severe cases, seizures or coma.
- The mechanism behind lamotrigine-induced hyponatremia likely involves inappropriate antidiuretic hormone secretion (SIADH), affecting water reabsorption in the kidneys, as suggested by studies including 2 and 3.
- Management typically involves addressing the underlying cause, which may require lamotrigine dose adjustment or discontinuation in consultation with a healthcare provider, and sodium levels should be corrected gradually to avoid complications like osmotic demyelination syndrome.
- Regular monitoring of electrolytes is advisable when starting lamotrigine, particularly in high-risk patients, as emphasized by the potential consequences of untreated hyponatremia, including increased morbidity and mortality, as discussed in 4.
Clinical Approach
- If a patient on lamotrigine develops symptoms suggestive of hyponatremia, sodium levels should be checked promptly.
- The use of vasopressin receptor antagonists may provide a promising treatment for hyponatremia, as they target the most common mechanism of increased vasopressin activity, but their use should be guided by the specific clinical context and the latest evidence, including considerations from 5 and 4.