Dytan suspension is used for: Preventing or treating symptoms of hay fever and other upper respiratory allergies or the common cold, such as runny nose, sneezing, itching of the nose and throat, and itchy, watery eyes, and relieving cough. It may also be used for other conditions as determined by your doctor. Dytan suspension is an antihistamine and anticholinergic. It works by blocking the action of histamine, reducing the symptoms of an allergic reaction. It also works in the brain to cause sedation.