Zyrtec is an antihistamine medication containing 10mg of cetirizine dihydrochloride per tablet. Available in a pack of 20 film-coated tablets, it is manufactured by GSK and used to treat allergy symptoms like sneezing, runny nose, and itchy eyes. Zyrtec tablets are film-coated for easy swallowing. The active ingredient cetirizine dihydrochloride works by blocking histamine, a substance that causes allergic symptoms. As this is a medication, proper dosage and usage instructions should be followed according to your healthcare provider's recommendations. Store in a cool, dry place away from direct sunlight.