1 interaction related to autoinduction
Both carbamazepine and St. John's Wort induce CYP3A4, the liver enzyme that primarily breaks carbamazepine down. The combined effect is hard to predict: carbamazepine already induces its own metabolism, so adding the herb may lower exposure most before that self-induction is fully established. The bigger danger comes at transitions — especially stopping St. John's Wort while still on carbamazepine, when the loss of enzyme induction can let carbamazepine levels climb toward toxicity.
