Histan is a chlorpheniramine maleate medication containing 4mg per tablet, used to treat allergy symptoms like sneezing, runny nose, itching, rashes, and watery eyes. Each pack contains 20 tablets designed for oral administration. This medication is intended for adults and children over 2 years old. Adults and children over 12 should take 4mg every 6 hours, not exceeding 24mg in 24 hours. Children 6-12 years should take 2mg every 6 hours (max 12mg/day), and children 2-6 years should take 1mg every 6 hours (max 6mg/day). Store at room temperature between 20-25°C. Do not take if allergic to ingredients, have glaucoma, enlarged prostate, urinary/intestinal obstruction, or during acute asthma attacks. Common side effect includes drowsiness. Consult doctor before use if pregnant or have other medical conditions.