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# Allegra (fexofenadine)
## Overview
- Second-generation H1-antihistamine; non-sedating at recommended doses.
- Active metabolite of terfenadine; no significant CYP450 metabolism.
## Primary Indications
- Seasonal allergic rhinitis (SAR)
- Chronic idiopathic urticaria (CIU)
## Adult Dosing
- **SAR/CIU**: 60 mg twice daily **OR** 180 mg once daily.
- Maximum: 180 mg/day.
## Pediatric Dosing
- **6–11 months** (SAR only, under physician guidance): 15 mg twice daily.
- **2–11 years** (SAR/CIU): 30 mg twice daily.
- **12 years and older**: same as adult dosing.
- *Note: Dosing for children <2 years may be off-label; consult local protocol.*
## Dose Adjustments
- **Renal impairment** (CrCl <80 mL/min): 60 mg once daily (adults).
- **Hepatic impairment**: no adjustment needed.
## Contraindications
- Hypersensitivity to fexofenadine or any component.
## Adverse Effects
- Most common: headache, drowsiness (less than first-generation antihistamines), nausea, dysmenorrhea.
- Rare: hypersensitivity reactions, palpitations.
## Key Drug Interactions
- **Aluminum/magnesium antacids**: reduce fexofenadine absorption; separate by ≥2 hours.
- **Fruit juices** (grapefruit, orange, apple): decrease bioavailability; avoid concomitant administration. Take with water.
## Monitoring
- Clinical: symptom relief (rhinitis, urticaria).
- No routine lab monitoring required.
## Clinical Pearls
- Take fexofenadine with water only; fruit juices can reduce absorption by up to 40%.
- Onset ~1 hour, duration ~24 hours (once-daily formulation).
- No significant sedation; does not impair driving at recommended doses.
- Not metabolized by CYP450; minimal drug–drug interactions.
> **Educational disclaimer:** This information is for educational purposes and does not replace clinical judgment. Dosing may vary by region and formulation; always verify current prescribing information.
