Doctors prescribe Fexofenadine hydrochloride to treat the symptoms of allergic rhinitis in adults and in children who are at least 2 years old, notes Drugs.com. They may also prescribe Fexofenadine hydrochloride for adults and children ages 6 months and older with chronic idiopathic urticaria-related skin problems.
Fexofenadine hydrochloride is available in the United States in doses of 30-, 60- and 180-milligrams, states Drugs.com. The side effects of Fexofenadine hydrochloride include headaches, back pain and vomiting. Antacids and fruit juices may reduce the effectiveness of the drug, and women who are nursing should use Fexofenadine hydrochloride with caution, due to lack of research on potential harmful side effects.