Dear Dr. Walt,
I take St. John’s wort for depression. My pharmacist told it can interact with quite a number of medications and even some foods. Would taking it several hours apart from other medications and between meals or at bedtime eating help avoid this interaction?
—Avoiding Unwanted Interactions in Utah
The short answer is, “Unfortunately not.”
Unlike mineral supplements (like calcium) which compete for absorption with other minerals and should ideally be taken apart from large doses of one another, the interactions of St. John’s wort are due to its effects on how drugs are metabolized after they have been absorbed.
So potential interactions can take place even if the drugs or foods are taken at a different time—even hours later.
What makes this more difficult is that most studies show that taking St. John’s wort three times a day is most effective, so there is not much time when it will not be active and potentially interfere with other drugs.