My wife has been using Benadryl every evening for years. Recently she has experienced heart racing, headaches. She has a brain shunt for hydrocephalus. I have notices she is more competitive on the highway and angrier at our dogs, including striking one of them repeatedly. This is not like her. She cannot get a full night s sleep without it but even with it she may only sleep part of the night or have intermittent periods of wakefulness.