Leader Allergy Relief D-12 provides powerful, 12hour relief from the toughest allergy symptoms. This "D" formula combines an antihistamine to stop sneezing and itchy/watery eyes with a nasal decongestant to clear sinus pressure and stuffy noses. The extended-release tablets are designed to deliver a steady dose of medication, allowing you to go through your day (or night) without the need for frequent dosing. It is particularly effective for hay fever, upper respiratory allergies, and the common cold.