Registered Practical Nurse (RPN) Practice Test

After three months of carbamazepine treatment, which laboratory deficiency should the nurse assess for?

1. Calcium

2. Vitamin B12

3. Vitamin D

4. Folic acid

The correct answer is: Vitamin B12

The correct answer is Vitamin B12. Carbamazepine is an anticonvulsant medication that is commonly used to treat seizure disorders and certain types of neuropathic pain. One of the known side effects of long-term carbamazepine use is its effect on folate metabolism, which can subsequently lead to vitamin B12 deficiency. While carbamazepine does not directly cause vitamin B12 deficiency, it is known to interfere with the metabolism of certain nutrients, particularly folic acid. However, the clinical impact of this can extend to B12 deficiency as well, as there is an intricate relationship between the two vitamins in terms of absorption and utilization within the body. Monitoring for vitamin B12 deficiency in patients receiving carbamazepine treatment is important because this deficiency can lead to neurological complications, including peripheral neuropathy and cognitive changes, which can significantly affect a patient's quality of life. Additionally, the other options, such as calcium, vitamin D, and folic acid, while each important, are not specifically known to be deficient as a direct result of carbamazepine therapy in the same manner as vitamin B12. Thus, assessing for vitamin B12 deficiency is a key nursing consideration in the ongoing management of patients on carbamazep