Fexofenadine, sold under the trade name Allegra, is an antihistamine pharmaceutical drug used in the treatment of allergy symptoms, such as hay fever, nasal congestion, and urticaria. Fexofenadine is also used to treat skin itching and hives caused by a condition called chronic idiopathic urticaria in adults and children.

How to take Fexofenadine. If you are using the liquid form of this medication, shake the bottle well before each dose and measure the dose carefully using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. Take the tablet/capsule or liquid form of this medication with or without food. If you are using the rapidly-dissolving tablet, take it on an empty stomach. Allow the rapidly-dissolving tablet to dissolve on the tongue and then swallow, with or without water.