A question about Eragon's spell

Would it have been possible for Eragon to remove the empathy spell that he used against Galabtorix? Let be clear and say that I don't in any way wish that Eragon would have done that. Galbatorix was evil and he 100% deserved to feel the pain that he felt during that moment, but whenn he begged Eragon to make it stop it got me thinking, would it even have been possible to remove the spell?