I'm sorry to relay that my stomach did not fare well on the z-pack years ago. I too try terribly to avoid antibiotics (since I think my abuse of them in the past may have led to my IBS...just my opinion), but if I do need to take something, I can tolerate cefzil or amoxicillin. If after a day or two of the z-pack you are having problems, just call the doctor and ask them to switch. Good luck and feel better.
-------------------- Originally IBS-D for a million years!
Then IBS-A, Now a transformed slightly C