migraine
"I was prescribed Periactin to help contain severe migraines and have found it very effective.  After taking two tablets a day for a week, I thought that maybe my migraines had been cured and stopped taking them- unfortunately, my headache came back within about 1 and a half days.  I am now taking regular doses again and have not had a single headache to complain of, however the increased appetite is an unfortunate side effect."