About Allegra.

Fexofenadine has been shown to exhibit minimal (ca. 5%) metabolism. However, co-administration of Fexofenadine hydrochloride with either ketoconazole or erythromycin led to increased plasma concentrations of Fexofenadine. Fexofenadine had no effect on the pharmacokinetics of either erythromycin or ketoconazole. In 2 separate studies, Fexofenadine hydrochloride 120 mg twice daily (240 mg total daily dose) was co-administered with either erythromycin 500 mg every 8 hours or ketoconazole 400 mg once daily under steady-state conditions to healthy volunteers (n=24, each study). No differences in adverse events or QTc interval were observed when subjects were administered Fexofenadine hydrochloride alone or in combination with either erythromycin or ketoconazole.

The changes in plasma levels were within the range of plasma levels achieved in adequate and well-controlled clinical trials.

The mechanism of these interactions has been evaluated in in vitro, in situ, and in vivo animal models. These studies indicate that ketoconazole or erythromycin co-administration enhances Fexofenadine gastrointestinal absorption. This observed increase in the bioavailability of Fexofenadine may be due to transport-related effects, such as p-glycoprotein. In vivo animal studies also suggest that in addition to enhancing absorption, ketoconazole decreases Fexofenadine gastrointestinal secretion, while erythromycin may also decrease biliary excretion.

Seasonal Allergic Rhinitis

Fexofenadine Hydrochloride Tablets are indicated for the relief of symptoms associated with seasonal allergic rhinitis in adults and children 6 years of age and older. Symptoms treated effectively were sneezing, rhinorrhea, itchy nose/palate/throat, itchy/watery/red eyes.

Chronic Idiopathic Urticaria

Fexofenadine Hydrochloride Tablets are indicated for treatment of uncomplicated skin manifestations of chronic idiopathic urticaria in adults and children 6 years of age and older. It significantly reduces pruritus and the number of wheals.

Before using fexofenadine, tell your doctor if you are allergic to any drugs, or if you have kidney disease.
Fruit juices and certain antacids can make it harder for your body to absorb fexofenadine. Take the disintegrating tablet on an empty stomach, at least 1 hour before or 2 hours after a meal.

There may be other drugs that can affect fexofenadine. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.
Stop using this medication and get emergency medical help if you think you have used too much medicine, or if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Less serious side effects are more likely, and you may have none at all. Tell your doctor about any unusual or bothersome side effect.

Tell your doctor if your symptoms do not improve, or if they get worse after you start taking fexofenadine. Never take more of the medication than your doctor has prescribed.