The entire culture will change even if Pfizer keeps you. I made it through the Wyeth process and the company and co-workers I loved working for/with changed overnight! The company I was left with only cared about the Pfizer culture which highlighted patient focused products/initiatives but really only cares about $$$! I look back and think I would have been better if I would have been "separated" at the beginning.
The process to be pushed into the Pfizer culture and the departure from the Wyeth "family" always made me feel like a square peg being pushed into a round hole. Pfizer colleagues cheer, protect, promote each other. It takes a lot of time to drink the blue kool aid and find your way!
Good luck and get ready for things to move fast once all the approvals are processed. Wyeth/Pfizer "merger" was announced in January and separation calls were made in October/November. After that the "new" Pfizer rolled out the internal processes changed at lightening speed. All the systems, policy's, products were converted to Pfizer almost overnight. People, territories and product focus was re-arranged without any understandable reasons. No regard to product experience and territory relationships. Which continues to happen today. You will be moved and switched to fit Pfizer's needs, not based on your experience or skill sets. And this may happen three times in a year, because it is what Pfizer wants/needs. No appreciation or consideration will be provided to you. Keep tally yourself and push for credit on your field activity reports and get ready to keep writing your mid year reviews, yearly reviews. The administrative bs is some days never ending!
Welcome to big blue! You want a "to go" glass of that?