The local pharmacist has little information about promethazine. I am concerned about taking orally or using dermatological application of promethazine with pain killers such as excedrin migraine for my severe and frequent migraines (2-4 times a month, sometimes lasting 3 days each). The neurologist prescribed it, but said nothing about all the potential side effects. I have only seen her twice, both times last year, because she is very expensive, and thus she really doesn t know my condition well, though I believe she is a good neurologist.