Dear patient thank you for your question. It is a very interesting one as the debate between generic and non generic medications is one that has been going on for years and no end seems in sight. However coming to your question, medically there is no difference or rather should not be any however many forums have reported complaints about the weak efficacy of the generic drugs One school of though is that it is old and expired due to incorrect storage or watered down. Therefore my suggestion is if you can afford it then switch back to your old medication If however you cannot give your body a month to adjust to it. That being said if the nausea and constipation become severe go back to your original irrespective. Also I must remind you to keep yourself hydrated at all times with ors and fluids as chemotherapy induced vomiting may lead to severe dehydration I wish you all the best