i can tell you that there are no negative drug interactions between dextromethorphan antihistamines and steroid nasal sprays. but i cannot tell you at this time if dextromethorphan is the best product to use for your daughter's type of cough. i suggest you talk with your health-care professional who will collect more information from you and make a recommendation.
my 7-year-old takes an otc antihistamine and steroid nasal spray but still has a cough. can i give her cough syrup?