First on the list of duds was ZzzQuil, an over-the-counter sleep aid from the makers of DayQuil and NyQuil. Sold as a syrup, ZzzQuil contains the active ingredient diphenhydramine, an ...

Additive effects with other antihistamines, anticholinergics, sedatives, tranquilizers or other nighttime cold/fu products (eg, NyQuil); avoid.