Domperidone and Metoclopramide together can potentially lead to an increased risk of side effects, both medications have similar mechanisms of action and may enhance each other's effects. They don't exactly act on the same receptor but it is still a bad idea to take the two together.
For example, if you take two antiemetics that act on the same receptor, you may get stronger anti-nausea effects but you'll experience side effects like sedation and dizziness, as well as extrapyramidial symptoms which are uncontrolled movements. In my opinion, its not peaceful and N is supposed to be peaceful but I guess you can do what you want.