It all depends on the anesthesia school. As a CRNP who also became a CRNA, I had to take all science courses all over again, since some if not most science courses in anesthesia school focused on "anesthesia" effects on the body.
I would check on each school's requirements (those that you plan to apply to).
Another issue that you might want to think about is the INTERVIEW process and what answer you will give the committee once they ask you "why do you want to become a CRNA? You just recently became a CRNP?"
Answering, "Because I want to make more money" is not going to go well with them in my own opinion.
I too am a CRNP and decided later on, after practicing for several years to become a CRNA. Although, my motives were entirely different than most people, I decided to become a dual role APN so that I can work in a dual role capacity in a rural setting. I will soon be realizing my dream in a few months, and will be working in a rural hospital in a DUAL role capacity in New Hampshire.
Some of the NPs that I know of who also became CRNAs are no longer working as a CRNP. Many, if not most admit that's because the money is better working as a CRNA alone. The committee members for CRNA schools
know this. Therefore, I do believe that they would rather accept a CRNP that is "seasoned" and have several years of advance practice experience under their belts, over one who just recently graduated. It also shows some type of committment by you to becoming a CRNP and working for a couple years, then going back to CRNA school.