A nurse is talking with a client who has been taking levothyroxine to treat hypothyroidism. The nurse should instruct the client to avoid taking which of the following over-the-counter medications within 4 hr of taking levothyroxine?

A. Calcium can interfere with the absorption of levothyroxine, so they should be taken separately. B. These do not interfere significantly with levothyroxine absorption. C. Fish oil supplements do not interfere significantly with levothyroxine absorption. D. Antihistamines do not interfere significantly with levothyroxine absorption.