s, I used to take Unisom for a sleep aide (
Diphenhydramine) although they no longer helped me sleep, I now take Lunesta#2 and I sleep ok, If you do confirm that Antihistamines affect Thtroid meds Please post what you find, I still take antihistamines for allergys, or if you could post where you read the article. I have a bottle of Unisom and the ingredient states it contains Diphenhydramine (An Antihistamine) not Doxylamine.