Oxcarbazepine causes hyponatremia, or low sodium levels, because it is a drug that blocks voltage-sensitive sodium channels, says RxList. Because of this, the neural membranes whose overexcitement leads to seizures are calmed and stabilized.
Fortunately, hyponatremia in patients who take oxcarbazepine is rare, according to RxList. However, people who start a course of the drug need to have their sodium levels monitored, especially if they have a history of low sodium levels.
Sodium is an electrolyte and is needed to control the amount of water in the body, says Mayo Clinic. If sodium levels are too low, water enters the cells of the body and causes them to swell. The symptoms of hyponatremia are nausea, vomiting, fatigue combined with restlessness and muscle weakness. Headache and confusion are also symptoms. In severe cases, the patient experiences seizures and eventually falls into a coma.
The side effects of oxcarbazepine can be considerable even without hyponatremia. They include drowsiness and dizziness that make it dangerous for the patient to drive, suicidal ideation and a skin condition called toxic epidermal necrolysis. People who have the HLA-B*1502 gene are at greater risk for this skin condition, which leads to blisters and large areas of the skin sloughing off, according to WebMD.