Yes, you can use Allegra 120mg with other medications in many cases, but there are some important precautions to keep in mind. Like any medication, Allegra 120mg can interact with certain drugs, which might reduce effectiveness or increase the risk of side effects. Unlike first-generation antihistamines, Allegra 120mg is a second-generation antihistamine, which means it is less likely to cause drowsiness or sedation, making it suitable for use during the day without impairing alertness. Allegra 120mg blocks H1 receptors, which prevents histamine from binding and triggering symptoms of allergy.