Hi Paula,   Thank you for your question! I'm not familiar with the term HBT, so I'm unable to answer that part of your question.   There is a probably drug interaction between the iron and the Nexium. However, there isn't a definite course of action to get around the interaction. The two should definitely not be taken at the same time. Nexium should be taken 1 hour before breakfast for best results. If that is the case, the iron can probably be safely taken 2-3 hours later. Because Nexium works for 24 hours, it may reduce the amount of iron that can be absorbed by the body. You should discuss with your doctor whether this is of concern in your case.   Best of luck, Casey