Allegra SIDE EFFECTS In placebo controlled clinical trials, which included 2461 patients receiving fexofenadine HCl at doses of 20 mg to 240 mg twice daily, adverse events were similar in fexofenadine HCl and placebo-treated patients. The incidence of adverse events, including drowsiness, was not dose related and was similar across subgroups defined by age, gender, and race. The percent of patients who withdrew prematurely because of adverse events was 2.2% with fexofenadine HCl vs 3.3% with placebo. All adverse events that were reported by greater than 1% of patients who received the recommended daily dose of fexofenadine HCl (60 mg twice-daily), and that were more common with fexofenadine than placebo, are listed in TABLE 2. TABLE 2 Adverse Experiences Reported in Placebo-Controlled Seasonal Allergic Rhinitis Clinical Trials at Rates of Greater Than 1%   Fexofenadine 60 mg Twice Daily Placebo Twice Daily Adverse Experience (n=679) (n=671)  Viral Infection (cold, flu) 2.5% 1.5%  Nausea 1.6% 1.5%  Dysmenorrhea 1.5% 0.3%  Drowsiness 1.3% 0.9%  Dyspepsia 1.3% 0.6%  Fatigue 1.3% 0.9% Adverse events occurring in greater than 1% of fexofenadine HCl-treated patients (60 mg twice daily), but that were more common in the placebo-treated group, include headache and throat irritation. The frequency and magnitude of laboratory abnormalities were similar in fexofenadine HCl and placebo-treated patients. DRUG INTERACTIONS In two separate studies, fexofenadine HCl 120 mg twice daily (twice the recommended dose) was co-administered with erythromycin 500 mg every 8 hours or ketoconazole 400 mg once daily under steady-state conditions to normal, healthy volunteers (n=24, each study). No differences in adverse events or QTc interval were observed when subjects were administered fexofenadine HCl alone or in combination with erythromycin or ketoconazole. The findings of these studies are summarized in TABLE 1. TABLE 1 Effects on Steady-State Fexofenadine Pharmacokinetics After 7 Days of Co-Administration with Fexofenadine HCl 120 mg Every 12 Hours (twice recommended dose) in Normal Human Volunteers (n=24) Concomitant Drug Cmax SS (Peak Plasma Concentration) AUCSS (0-12h) (Extent of Systemic Exposure)  Erythromycin (500 mg every 8 hours) +82% +109%  Ketoconazole (400 mg once daily) +135% +164% The mechanisms of these interactions are unknown, and the potential for interaction with other azole antifungal or macrolide agents has not been studied. These changes in plasma levels were within the range of plasma levels achieved in adequate and well-controlled clinical trials. Fexofenadine had no effect on the pharmacokinetics of erythromycin or ketoconazole. Buy Allegra Now   Buy Allegra Now