Chlorpheniramine is an antihistamine commonly used to relieve allergy symptoms such as sneezing, runny nose, and itchy eyes. It works by blocking the action of histamine, a substance in the body that causes allergic reactions. Chlorpheniramine is often found in over-the-counter medications for colds and allergies. This medication can cause drowsiness, so it is important to avoid driving or operating heavy machinery after taking it. Chlorpheniramine is available in various forms, including tablets and liquid, and is typically taken every 4 to 6 hours as needed. Always follow the dosage instructions provided by a healthcare professional.