American Board of Internal Medicine (ABIM) Certification Practice Exam

What is recommended for monitoring serum sodium levels after initiating carbamazepine or oxcarbazepine?

1. At 1 month and 6 months

2. At 3 months and yearly thereafter

3. At 3 months and 6 months

4. At monthly intervals for the first year

The correct answer is: At 3 months and 6 months

The recommendation for monitoring serum sodium levels after initiating carbamazepine or oxcarbazepine is based on the potential of these medications to cause hyponatremia, particularly in certain populations such as older adults or those with underlying conditions. These drugs can lead to inappropriate secretion of antidiuretic hormone (SIADH), which can affect sodium levels. Monitoring at intervals of 3 months and 6 months following initiation allows for sufficient time to evaluate any changes in sodium levels that may arise as the patient continues therapy. At the 3-month mark, there is an opportunity to detect any early alterations due to the medications, while a follow-up at 6 months provides a subsequent check to ensure that sodium levels remain stable and within a safe range, potentially allowing for timely intervention if any issues are identified. The frequency of monitoring beyond this time frame may vary based on individual risk factors and clinical guidelines but the initial period typically emphasizes these intervals to capture and address potential side effects associated with these agents effectively.