-- Question: What over-the-counter medications are used to treat seasonal allergies?
Answer: There are several medications that are available over-the-counter. The most common of these are the antihistamines. Antihistamines work for the symptoms of runny nose, sneezing and itching and are not as effective for nasal congestion. The main side effects from antihistamines are sedation and dry mouth and this can vary depending on the type of antihistamine that is used.
Another common medication for allergies are decongestants. Decongestants can be both in a pill form or as a nasal spray. Pill decongestants work simply for the symptom of congestion in the nose and the main side effect is that of insomnia, difficulty sleeping and sometimes agitation.
Topical nasal decongestant sprays also are the most effective thing for stuffy noses. The main side effect with these medications is, if used for a long term -- mainly several weeks -- one can develop a rebound effect and develop congestion on top of what you are trying to treat.
Finally, nasal cromolyn is a allergy medication that is available over-the-counter. Generally this medication is not terribly effective and must be used about four times a day to get maximal benefit.