Fexofenadine hydrochloride, the major active metabolite of terfenadine, is an antihistamine with selective peripheral H1-receptor antagonist activity. This observed increase in the bioavailability of fexofenadine may be due to transport-related effects, such as p-glycoprotein.
Fruit juices such as grapefruit, orange and apple may reduce the bioavailability and exposure of fexofenadine Allegra 180 Mg . Fexofenadine hydrochloride pharmacokinetics are linear for oral doses up to a total daily dose of 240 mg (120 mg twice daily). The pharmacokinetics of fexofenadine hydrochloride in subjects with seasonal allergic rhinitis and subjects with chronic urticaria were similar to those in healthy subjects. After administration of a single 60 mg capsule to healthy subjects, the mean maximum plasma concentration (Cmax) was 131 ng/mL. The aqueous tablet film coating is made from hypromellose, iron oxide blends, polyethylene glycol, povidone, silicone dioxide, and titanium dioxide. Allegra 180 Mg 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. In vivo animal studies also suggest that in addition to enhancing absorption, ketoconazole decreases fexofenadine gastrointestinal secretion, while erythromycin may also decrease biliary excretion. Although the number of subjects in some of the subgroups was small, there were no significant differences in the effect of fexofenadine hydrochloride across subgroups of subjects defined by gender, age, and race. The mean elimination half-life of fexofenadine was 14.4 hours following administration of 60 mg twice daily in healthy subjects. The clinical significance of these findings is unknown. Co-administration of 180 mg fexofenadine hydrochloride tablet with a high fat meal decreased the mean area under the curve (AUC) and (Cmax) of fexofenadine by 21 and 20% respectively. Radiolabeled tissue distribution studies in rats indicated that fexofenadine does not cross the blood-brain barrier. Although all 4 doses were significantly superior to placebo, symptom reduction was greater and efficacy was maintained over the entire 4-week treatment period with fexofenadine hydrochloride doses of 60 mg twice daily. In laboratory animals, no anticholinergic or alpha1-adrenergic blocking effects were observed. However, no additional benefit of the 120 or 240 mg fexofenadine hydrochloride twice daily dose was seen over the 60 mg twice daily dose in reducing symptom scores. It is freely soluble in methanol and ethanol, slightly soluble in chloroform and water, and insoluble in hexane. The administration of the 60 mg capsule contents mixed with applesauce did not have a significant effect on the pharmacokinetics of fexofenadine in adults. Onset of action for reduction in total symptom scores, excluding nasal congestion, was observed at 60 minutes compared to placebo following a single 60 mg fexofenadine hydrochloride dose administered to subjects with seasonal allergic rhinitis who were exposed to ragweed pollen in an environmental exposure unit. The tablet formulations are bioequivalent to the capsule when administered at equal doses.