Patented in 1981, cetirizine is an allergy medication that you can buy over-the-counter at a pharmacy. That is, you don’t need a prescription in order to be able to get it. This medication is used to treat hay fever, dermatitis, and urticaria. It is worth mentioning that when you come in contact with allergens, your body produces a chemical called histamine, which in turn causes most of the symptoms related to allergic reactions. Considering Cetirizine is an antihistamine, its initial role is to block the effects of histamine. Therefore, it helps relieve mild to moderate allergy symptoms such as sneezing, runny nose, itchy or watery eyes and itchy throat or nose. Typically, the previously mentioned reactions happen after you touch or inhale allergens such as plant pollen, mold, or pet dander. When it comes to its side effects, cetirizine is unlikely to cause side effects like dangerous drowsiness, dry mouth, blurred vision, and overheating. However, it can cause adverse effects such as excessive tiredness and diarrhea. And even though the use of this medication in pregnancy appears safe, its use during breastfeeding is not recommended.