Question: how much antihistamine can you take per day?
Answer: Adults—25 to 100 milligrams (mg) three or four times a day as needed. Children 6 years of age and older—12.5 to 25 mg every six hours as needed. Children 4 to 6 years of age—12.5 mg every six hours as needed. Children and infants up to 4 years of age—Use is not recommended .