PHARMACODYNAMICS Allegra (Fexofenadine)

Allegra (Fexofenadine) is an antihistamine with selective peripheral H_i -receptor antagonist activity. Allegra (Fexofenadine) inhibited antigen-induced bronchospasm in sensitized guinea pigs and histamine release from peritoneal mast cells in rats. In laboratory animals,no anticholinergic or alphal -adrenergic-receptor blocking effects were observed. Moreover, no tranquilizer or other central nervous system effects were experienced. Radio labeled tissue allocation studies in rats specified that Allegra (Fexofenadine) does not cross the blood-brain barrier.

Fexofenadine hydrochloride inhibits skin - wheat and flare responses produced by histamine injection. Following single and twice daily oral dose supervision, antihistaminic effects occurred within 1 hour, achieved a maximum of 2-3 hours, and lasted a minimum of 12 hours. Maximum inhibition in skin wheal and flare areas was greater than 80%. There is no verification of forbearance to these effects after 28 days of dosing. Using philosophical total indication score evaluation as the most important endpoint, clinical studies conducted in recurring allergic rhinitis have shown that a dose of 120 mg is adequate for 24 hour efficiency. In children aged 6 to 11 years, the suppressive effects of Fexofenadine on histamine - induced wheal and flare were comparable to that in adults at similar exposure.

ln an integrated analysis of placebo-controlled double-blind phase III studies, involving 1369 children with seasonal allergic rhinitis aged 6 to 11 years, Fexofenadine hydrochloride at 30 mg twice daily was significantly than placebo in reducing total symptom score (p=0.0001).

The effectiveness of Fexofenadine hydrochloride 30 mg twice daily for the healing of regular allergic rhinitis in patients 2 to 5 years of age is based on the pharmacokinetic assessments in adult and pediatric subjects and an extrapolation of the verified effectiveness of Fexofenadine hydrochloride in adult and older pediatric subjects with this circumstance and the probability that the disease course, pathophysiology, and the drug's effect are significantly analogous in pediatric patients to those in adult patients.

The efficacy of Allegra (Fexofenadine) for the healing of chronic idiopathic urticaria in patients 6 months to 11 years of age is based on the pharmacokinetic comparisons in adults and children and an extrapolation of the verified efficiency of Allegra (Fexofenadine) in adults with this stipulation and the likelihood that the disease course, pathophysiology and the drug's effect are considerably comparable in children to that of adult patients.