Allegra%20%28fexofenadine%29

# Allegra (fexofenadine) ## Overview Fexofenadine is a second-generation, non-sedating antihistamine—a peripheral H1-receptor antagonist. It does not cross the blood-brain barrier significantly, reducing CNS depression. ## Primary Indications - Seasonal allergic rhinitis (hay fever) - Chronic idiopathic urticaria (hives) ## Adult Dosing **Seasonal allergic rhinitis:** - 60 mg twice daily **or** 180 mg once daily **Chronic urticaria:** - 60 mg twice daily **or** 180 mg once daily Max: 180 mg/day. ## Pediatric Dosing **Children 6–11 years:** - 30 mg twice daily (seasonal allergic rhinitis or urticaria) **Children 2–5 years (chronic urticaria only):** - 15 mg twice daily **Children <2 years:** Safety/efficacy not established; consult pediatric specialist. ## Dose Adjustments **Renal impairment (CrCl <80 mL/min):** - Adults: 60 mg once daily - Pediatrics: adjust per local protocol **Hepatic impairment:** - No adjustment needed. **Elderly:** - Use lowest effective dose; no specific adjustment required but caution with renal function. ## Contraindications - Known hypersensitivity to fexofenadine or any component ## Adverse Effects Common: headache, drowsiness (rare vs older antihistamines), nausea, dysmenorrhea Rare: hypersensitivity reactions, dizziness, cough, fatigue ## Key Drug Interactions - **Antacids (aluminum/magnesium):** reduce fexofenadine absorption—separate by ≥2 hours - **Fruit juices (apple, orange, grapefruit):** decrease absorption—avoid co-administration - **Erythromycin, ketoconazole:** increase fexofenadine levels but no significant QTc prolongation noted in studies ## Monitoring - Clinical response (symptom relief) - Renal function in at-risk populations ## Clinical Pearls - Take on an empty stomach for best absorption (food slightly decreases absorption). - Not significantly sedating; may be preferred for daytime use. - Onset of action ~1–3 hours, duration ~24 hours (once-daily dosing). - Safe in mild-to-moderate hepatic impairment. *Always verify current prescribing information with a trusted drug reference or local formulary.*