A dose of 5 mL of ALLEGRA Oral Suspension containing 30 mg of fexofenadine hydrochloride is bioequivalent to a 30 mg dose of ALLEGRA tablets. 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. ALLEGRA Oral Suspension, a white uniform suspension, contains 6 mg fexofenadine hydrochloride per mL and the following excipients: propylene glycol, edetate disodium, propylparaben, butylparaben, xanthan gum, poloxamer 407, titanium dioxide, sodium phosphate monobasic monohydrate, sodium phosphate dibasic heptahydrate, artificial raspberry cream flavor, sucrose, xylitol and purified water. 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. 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 one 2-week, multicenter, randomized, double-blind clinical trial in subjects 12 to 65 years of age with seasonal allergic rhinitis (n=863), fexofenadine hydrochloride 180 mg once daily 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. The administration of the 60 mg capsule contents mixed with applesauce did not have a significant effect on the pharmacokinetics of fexofenadine in adults. Similar reductions were observed for mean number of wheals and mean pruritus score at the end of the 24-hour dosing interval. The mean elimination half-life of fexofenadine was 14.4 hours following administration of 60 mg twice daily in healthy subjects.
Following single dose oral administrations of either the 60 and 180 mg tablet to healthy adult male subjects, mean Cmax were 142 and 494 ng/mL, respectively. 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 clinical trial conducted with ALLEGRA 60 mg capsules, and in 1 clinical trial conducted with ALLEGRA-D 12 Hour extended release tablets, onset of action was seen within 1 to 3 hours. In laboratory animals, no anticholinergic or alpha1-adrenergic blocking effects were observed.
Fexofenadine hydrochloride, the major active metabolite of terfenadine, is an antihistamine with selective peripheral H1-receptor antagonist activity. Fexofenadine hydrochloride is a white to off-white crystalline powder.