I called Pfizer (800) 438-1985 and asked them about the difference between the old Dilantin and the new Dilantin. This is what I was told:
1. The capsules are different. The two halves of the old one were sealed with a band, and the new one is self-locking.
2. The ingredients are bioequivalent, but they may not be identical in type or quantity. That means that tests indicate that the body reacts virtually the same to both versions.
3. The ingredients are secret. The amounts are secret. Sugar is likely to be one of the ingredients in the old or new versions (or both).
5. They received a call yesterday from someone asking if aspartame had been added to the new formula.
6. Pfizer thanked me for my "concerns" (God, how I hate that word), and they got an earful from me about their failure to communicate effectively with their customers.