Fexofenadine is a drug that is typically prescribed to treat the symptoms of hay fever, also known as seasonal allergic rhinitis. The medication can also be used to treat hives and other conditions of the skin due to chronic idiopathic urticaria. It blocks a naturally-occurring substance in the body called histamine that causes the reaction to environmental allergens. Some of the symptoms it treats include sneezing, runny nose, watery eyes, and itchy nose and throat. It is most commonly sold under the product name Allegra®.
The drug is in the antihistamine drug class. It is meant to treat symptoms, rather than to provide a cure for allergies or uritacaria. The medication blocks histamine by preventing it from attaching to receptors in the body, thus avoiding the resulting discomfort from this kind of attachment.
Fexofenadine is taken orally and is available in liquid suspension and tablet form. A typical dosage is to take the drug one or two times daily with a full glass of water. It should not be taken with any kind of fruit juice as this can weaken the effect of the drug.
As some drugs and supplements can have an adverse interaction with fexofenadine, it is important for a patient to disclose everything he or she is taking to the prescribing doctor. The drugs ketoconazole and erythromycin in particular could be problematic. Antacids with magnesium or aluminum can also affect absorption of the drug, and should be taken at least a few hours away from the time the fexofenadine is administered.
There are some conditions which may make taking fexofenadine too risky or require extra supervision by a doctor during treatment. Women who are nursing, pregnant, or planning to become pregnant are usually advised not to take the drug. Patients who have or have had kidney disease should also disclose their condition to a doctor.
Mild side effects of fexofenadine need only be discussed with a doctor if they persist or become more severe. They include vomiting, diarrhea, headache, and dizziness. Some patients may also have a cough or experience pain in the back, legs, or arms.
The most common severe side effect of fexofenadine is an allergic reaction to the drug. Symptoms include itching, rash, and hives. There may also be swelling in several areas of the body including the lower legs and ankles, feet, hands, face, tongue, and throat. Some patients may experience hoarseness or have problems swallowing or breathing. These symptoms should receive immediate medical attention.