Drowsiness is a side effect of some antihistamines such as diphenhydramine (Benadryl) and doxylamine succinate (found in Nyquil). And because of their powerful sedating qualities, antihistamines are also the active ingredient in sleep aids.
Drowsiness is a side effect of some antihistamines such as diphenhydramine (Benadryl) and doxylamine succinate (found in Nyquil). And because of their powerful sedating qualities, antihistamines are also the active ingredient in sleep aids.