Cetirizine 10mg tabs, a generic brand equivalent to Zyrtec, is now available over-the-counter. The ingredient Cetirizine has been available for years in the form of a prescription called Zyrtec but now it is available as an over-the-counter product. Cetirizine 10mg tabs provide prescription-strength, 24-hour, indoor and outdoor allergy relief. It provides relief from sneezing, runny nose, itchy watery eyes and itchy throat or nose. Cetirizine is a once a day, fast acting medication that relieves symptoms of indoor and outdoor allergies in as little as 1 hour.