In addition, other medications may interact with oral decongestants causing side effects. Both of these are available as single products or in combination with a pain reliever or an antihistamine. Some medications are combined to reduce the number of pills. Antihistamine medications Antihistamines combat allergic problems leading to nasal congestion. They relieve the drainage associated with the allergic inflammation but not obstruction or congestion.
Antihistamines have a potential for sedation causing grogginess and dryness after use.
Newer nonsedating antihistamines are available. Antihistamine-decongestant combination products Antihistamines and decongestant products are often combined to relieve multiple symptoms of congestion and drainage and reduce the side effects of both products. The combined allergy product then relieves congestion and a runny nose.