I have terrible migraines, which were made much worse due to being hit in the head with a car doing 80mph. I found that 1 particular manufacturer generic brand made them worse, and also did not work as well. Several people i know also said they found that brand to be less effective than others.
The brand we dislike is called core pharmaceuticals inc. They make the 20mg round pink pills. The round peach ones work fine, but the oval shaped peach colored ones work best for me. My doctor had it put in my files at the pharmacy to never give me that brand.