 [ Symptoms ] my husband wants to know if its ok to take zyrtec and his sleeping pill which contains diphenhydramine 50mg  he uses an equate sleeping pill from wal wart and the active ingredient is diphenhydramine 50mg same as taking 2 benadryl is we are confused by that [ Disease ] they are both antihistamines the zyrtec is purported to be a non sedating antihistamine and diphenhydramine benadryl is a sedating antihistamine when used as a sleep aid it can interfere with deep restful dream like states so personally i am not a big fan of using it if he wants to use both then just take the zyrtec in the morning the diphenhydramine wears off in about 4 hours so it will be gone