A 42-yeаr-оld mаle with Bipоlаr I disоrder has been initiated on Carbamazepine 200 mg twice daily for mood stabilization. After two weeks of treatment, the patient reports a return of his hypomanic symptoms. Laboratory evaluation reveals that his serum carbamazepine level has dropped significantly below the expected therapeutic threshold, despite strict medication adherence confirmed by his spouse. What pharmacokinetic mechanism explains this drop in serum concentration, and how does it affect co-administered medications?