Zyrtec-D contains an additional ingredient, pseudoephedrine, a nasal decongestant. Cetirizine is an over-the-counter (OTC) antihistamine. Pseudoephedrine is a decongestant. Zyrtec-D is an OTC ...

Zyrtec’s active ingredient is cetirizine, which was introduced much later – in 1995 for prescription use and as an OTC option in 2007. “Benadryl doesn't break down well in humans ...