Fexofenadine
AllegraPubChem CID 3348 · 3D model
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Blocks histamine at the receptors outside the brain that trigger sneezing, itching, and hives, without crossing into the brain to cause drowsiness.
How it works
Fexofenadine is the active form of an older antihistamine that your body naturally converts it from, and it works by physically blocking histamine from attaching to its receptors in blood vessels, airways, and skin — the process that causes allergy symptoms. Unlike older allergy medicines, it doesn't meaningfully affect the chemical systems that control things like heart rate or dry mouth, so side effects like that are rare. A transport protein in the body actively pumps the drug back out before it can build up in the brain, which is why it causes little to no drowsiness. It starts working within about an hour and keeps working for 12 to 24 hours.
What it’s used for
Used to relieve seasonal allergy symptoms — sneezing, runny nose, and itchy, watery eyes — from hay fever and other airborne allergies. Also used to treat the itching and hives of chronic idiopathic urticaria, a long-term hive condition with no identified trigger.
- Mechanism
- Second-generation H1 histamine receptor antagonist
- Drug class
- Small molecule
- Therapeutic area
- Allergy / Immunology