What is promethazine dm?

PROMETHAZINE (proe-METH-a-zeen) and DEXTROMETHORPHAN (dex-troe-meth-OR-fan). This medicine is a phenothiazine antihistamine and cough suppressant combination used to treat cough and to relieve runny nose, sneezing, or watery eyes due to colds, flu, allergy, or hay fever. It may also be used for other conditions as determined by your doctor. WARNING: THIS MEDICINE MAY CAUSE SEVERE AND SOMETIMES FATAL BREATHING PROBLEMS in children less than 2 years of age.