Promethazine DM is a combination medication used to temporarily treat runny nose, coughing, and sneezing caused by the common cold, allergies, hay fever, and other breathing illnesses. It contains two active ingredients: promethazine and dextromethorphan. Promethazine is an antihistamine that helps to relieve symptoms such as itching, runny nose, and sneezing, while dextromethorphan is a cough suppressant that works by blocking the cough reflex.

It is important to note that promethazine should not be used by children younger than 2 years since it might cause serious (possibly fatal) slow/shallow breathing. This problem has occurred even with normal doses in this age group. The lowest effective dosage should be used, and other drugs that affect breathing should be avoided. Get medical help right away in the unlikely event that slow/shallow breathing occurs. Promethazine should not be used by children with liver disease (including possible Reyes syndrome) .

Before taking this medication, tell your doctor or pharmacist if you are allergic to promethazine or to dextromethorphan; or to any other phenothiazines (such as prochlorperazine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Promethazine DM should be used exactly as directed on the label or as prescribed by a doctor. It should not be used in larger or smaller amounts or for longer than recommended. It is important to follow all directions on the prescription label and read all medication guides or instruction sheets. The medicine should be stored at room temperature away from moisture and heat, and the bottle should be tightly closed when not in use.