Loratadine
ClaritinPubChem CID 3957 · 3D model
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Blocks histamine, the chemical that triggers sneezing and itching during an allergic reaction, but stays mostly out of the brain — so it controls symptoms without much drowsiness.
How it works
Loratadine works by plugging into the same docking sites, called H1 receptors, that histamine, the chemical your body releases during an allergic reaction, normally uses to trigger sneezing, itching, and watery eyes. It's built to stay mostly out of the brain, so it doesn't block the histamine receptors there that cause drowsiness the way older allergy medicines do. Once swallowed, the liver converts it into an active byproduct that keeps working in the body, which is why one dose can control symptoms for a full day.
What it’s used for
Labeled for temporary relief of classic allergy symptoms — runny nose, sneezing, itchy or watery eyes, and itchy nose or throat — caused by hay fever or other upper-respiratory allergies.
- Mechanism
- Second-generation H1 histamine receptor antagonist
- Drug class
- Small molecule
- Therapeutic area
- Allergy / Immunology