Hi there! Well my regime was different but in answer to your question, carbo is an older drug but as far as I know works just as effectively. He should be switched if for no other reason than the ear issues! They do this commonly if there is concern about his hearing being affected. With regards to taking a week off. I was set up for cis x 3 - full dose. They started me a week late - I had one week where my white cells were too low so the put my second dose off for another week, and then gave me # 2 - by number three's time I'd run out of radiation! So they didn't give it to me even though I actually wanted it. She told me this happens a lot, and people are ok. Sometimes they fail to get the 3rd full dose in. So ultimately that's about 2 of the small doses! I don't think it's a bad thing however, see how he does on the carbo, first. They'll stop him if they feel he needs a break. Good luck! And hugs!