Fruit juices such as grapefruit, orange and apple may reduce the bioavailability and exposure of fexofenadine Cheapest Allegra D . In vivo animal studies also suggest that in addition to enhancing absorption, ketoconazole decreases fexofenadine gastrointestinal secretion, while erythromycin may also decrease biliary excretion. In 1 of these 2 studies, conducted in 411 pediatric subjects, all 3 doses of fexofenadine hydrochloride significantly reduced total symptom scores (the sum of the individual scores for sneezing, rhinorrhea, itchy nose/palate/throat, itchy/watery/red eyes) compared to placebo, however, a dose-response relationship was not seen.
The tablet formulations are bioequivalent to the capsule when administered at equal doses. This observed increase in the bioavailability of fexofenadine may be due to transport-related effects, such as p-glycoprotein. Fexofenadine hydrochloride was rapidly absorbed following oral administration of a single dose of two 60 mg capsules to healthy male subjects with a mean time to maximum plasma concentration occurring at 2.6 hours post-dose. The mechanism of these interactions has been evaluated in in vitro, in situ, and in vivo animal models. The administration of 30 mg ALLEGRA Oral Suspension with a high fat meal decreased the AUC and the mean Cmax by approximately 30 and 47%, respectively in healthy adult subjects.

The 60 mg twice daily dose did not provide any additional benefit over the 30 mg twice daily dose in pediatric subjects 6 to 11 years of age. Fexofenadine hydrochloride inhibited antigen-induced bronchospasm in sensitized guinea pigs and histamine release from peritoneal mast cells in rats.
Because the absolute bioavailability of fexofenadine hydrochloride has not been established, it is unknown if the fecal component represents primarily unabsorbed drug or the result of biliary excretion. Fexofenadine Cheapest Allegra D the major active metabolite of terfenadine, is an antihistamine with selective peripheral H1-receptor antagonist activity. Administration of a 30 mg dose to pediatric subjects 2 to 11 years of age produced exposures Cheapest Allegra D to those seen with a dose of 60 mg administered to adults. The clinical significance of these findings is unknown. There were no significant differences in the effect of fexofenadine hydrochloride across subgroups of subjects defined by gender, age, weight, and race.
These studies indicate that ketoconazole or erythromycin co-administration enhances fexofenadine gastrointestinal absorption. Pharmacokinetics in renally and hepatically impaired subjects and geriatric subjects, obtained after a single dose of 80 mg fexofenadine hydrochloride, were compared to those from healthy subjects in a separate study of similar design. Statistically significant reductions in symptom scores were observed following the first 60 mg dose, with the effect maintained throughout the 12-hour interval.