Allegra

Human histamine skin wheal and flare studies following single and twice daily doses of 20 and 40 mg Fexofenadine hydrochloride demonstrated that the drug exhibits an antihistamine effect by 1 hour, achieves maximum effect at 2 to 3 hours, and an effect is still seen at 12 hours. There was no evidence of tolerance to these effects after 28 days of dosing. The clinical significance of these observations is unknown.

Histamine skin wheal and flare studies in 7 to 12 year old subjects showed that following a single dose of 30 or 60 mg, antihistamine effect was observed at 1 hour and reached a maximum by 3 hours. Greater than 49% inhibition of wheal area, and 74% inhibition of flare area were maintained for 8 hours following the 30 and 60 mg dose.

Pharmacokinetics in special populations (for renal, hepatic impairment, and age), obtained after a single dose of 80 mg Fexofenadine hydrochloride, were compared to those from healthy volunteers in a separate study of similar design.

Geriatric Subjects

In older subjects (≥65 years old), peak plasma levels of Fexofenadine were 99% greater than those observed in younger subjects (<65 years old). Mean Fexofenadine elimination half-lives were similar to those observed in younger subjects.

Pediatric Subjects

Cross study comparisons indicated that Fexofenadine area under the curve (AUC) following oral administration of a 60 mg dose of Fexofenadine hydrochloride to 7–12 year old pediatric subjects with allergic rhinitis was 56% greater compared to healthy adult volunteers given the same dose. Plasma exposure in pediatric subjects given 30 mg Fexofenadine hydrochloride is comparable to adults given 60 mg.

Renally Impaired

In subjects with mild to moderate (creatinine clearance 41–80 mL/min) and severe (creatinine clearance 11–40 mL/min) renal impairment, peak plasma levels of Fexofenadine were 87% and 111% greater, respectively, and mean elimination half-lives were 59% and 72% longer, respectively, than observed in healthy volunteers. Peak plasma levels in subjects on dialysis (creatinine clearance ≤10 mL/min) were 82% greater and half-life was 31% longer than observed in healthy volunteers. Based on increases in bioavailability and half-life, a dose of 60 mg once daily is recommended as the starting dose in patients with decreased renal function. (See DOSAGE AND ADMINISTRATION).

Hepatically Impaired

The pharmacokinetics of Fexofenadine in subjects with hepatic disease did not differ substantially from that observed in healthy volunteers.

Effect of Gender

Across several trials, no clinically significant gender-related differences were observed in the pharmacokinetics of Fexofenadine hydrochloride.

Fexofenadine hydrochloride was rapidly absorbed following oral administration of a single dose of two 60 mg capsules to healthy male volunteers with a mean time to maximum plasma concentration occurring at 2.6 hours post-dose. After administration of a single 60 mg capsule to healthy volunteers, the mean maximum plasma concentration was 131 ng/mL. Following single dose oral administrations of either the 60 and 180 mg tablet to healthy adult male volunteers, mean maximum plasma concentrations were 142 and 494 ng/mL, respectively. The tablet formulations are bioequivalent to the capsule when administered at equal doses. Fexofenadine hydrochloride pharmacokinetics are linear for oral doses up to a total daily dose of 240 mg (120 mg twice daily). The administration of the 60 mg capsule contents mixed with applesauce did not have a significant effect on the pharmacokinetics of Fexofenadine in adults.

Co-administration of 180 mg Fexofenadine hydrochloride tablet with a high fat meal decreased the AUC and Cmax of Fexofenadine by 21 and 20% respectively.