Health - Long Term Effects of Diphenhydramine?

[xyccoc]

SWIM has, every day for the past two years, been taking between 375mg and 625mg of diphenhydramine before bed (usually 2-3 hours before.) He or she started using it because of insomnia, but got into chronic use after falling in love with its mellowing recreational effects. In the long term, SWIM has not encountered any noticeable health problems, but is curious if there are any he or she would be aware of? SWIM knows it isn't a good idea, for obvious reasons, but he or she so far has no reason to stop.