A client with tonic-clonic seizure is receiving phenobarbital (Luminal) and valproic acid (Depakene). The nurse tells the client that:
A. Valproic acid decreases phenobarbital metabolism.
B. Valproic acid increases phenobarbital metabolism.
C. There is no interaction between the two.
D. Increase the dosage of the two medications.
Correct Answer: A. Valproic acid decreases phenobarbital metabolism.
Valproic acid appears to decrease phenobarbital metabolism, thus there is increased levels of phenobarbital in the body. Therefore, phenobarbital blood levels should be monitored and appropriate dosage adjustments made as indicated.