Read more about mast cells on Dr. Theoharides site and the antihistamine called Atarax (hydroxyzine) which crosses the BBB. I had to start with only tiny pieces of a pill during the day or I’d be too sleepy but I’m now able to take 10mg doses during the day without feeling sleepy. I take 25 mg at night and awake in the morning feeling rested and not groggy. The difference in my cognitive function has been dramatic and I’m off my ADHD-inattentive meds completely. My memory, attention, and problem solving have dramatically improved and I haven’t had any major mast cell degranulation episodes. My resting heart rate is lower now too.