Final answer:
Antacids should be taken at least 4 hours apart from levothyroxine to avoid interference with its absorption.
Step-by-step explanation:
Antacids should be taken at least 4 hours apart from levothyroxine. Antacids, which are used to neutralize stomach acid, can interfere with the absorption of levothyroxine, a medication used to treat an underactive thyroid. Taking antacids too close to levothyroxine can reduce its effectiveness, so it is important to separate the two medications by a sufficient time interval.