Sniffle and Cough Combinations OTC drugs to relieve stuffy noses often contain more than one ingredient. Some of these products are marketed for allergy relief and others for colds. They usually contain both an antihistamine and a nasal decongestant. But some of these products may also contain aspirin or acetaminophen, and some contain a decongestant alone. Others are immediate-release products and usually work for four to six hours.
Most antihistamines can cause drowsiness, while many decongestants have the opposite effect.
So it's best not to drive or operate machinery until you find out how the drug affects you. In addition, alcohol, sedatives and tranquilizers intensify the drowsiness effect of antihistamines, so it's best not to take them at the same time unless a doctor tells you to. Some brand names of products containing both antihistamines and decongestants are Allerest, Actifed and Dimetapp. Brand names of products that contain only antihistamines include Dimetane, Chlor-Trimeton and Benadryl. Sinus Headache contain antihistamines, decongestants and acetaminophen.