American Board of Internal Medicine (ABIM) Certification Practice Exam

Carbamazepine and oxcarbazepine are associated with which of the following?

1. Hyperkalemia

2. Hypomagnesemia

3. Hyponatremia

4. Hypocalcemia

The correct answer is: Hyponatremia

Carbamazepine and oxcarbazepine are known to be associated with hyponatremia, which is a condition characterized by low sodium levels in the blood. This occurs because both medications can induce the secretion of antidiuretic hormone (ADH), leading to water retention and dilutional hyponatremia. The mechanism behind this effect is linked to the sodium-wasting properties of these medications. They are associated with the development of the Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH), whereby excess ADH results in urinary retention of water, ultimately lowering serum sodium levels. Hyponatremia can cause various symptoms such as headache, confusion, and seizures; hence, it is crucial for healthcare providers to monitor sodium levels in patients prescribed these drugs. The other options refer to different electrolyte imbalances that are generally not associated with carbamazepine and oxcarbazepine. Hyperkalemia has different management considerations and causes unrelated to these antiepileptics. Hypomagnesemia and hypocalcemia also arise from distinct clinical scenarios that do not typically involve the use of carbamazepine or oxcarbazepine. Thus, the primary focus remains on the risk of