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# Fexofenadine (Allegra)
## Overview
Fexofenadine is a second-generation antihistamine that selectively blocks peripheral H1 receptors. It is a metabolite of terfenadine.
## Primary Indications
* Allergic rhinitis (seasonal and perennial)
* Chronic idiopathic urticaria
## Adult Dosing
* **Allergic rhinitis:** 180 mg orally once daily.
* **Chronic idiopathic urticaria:** 180 mg orally once daily.
## Pediatric Dosing
* **Allergic rhinitis/Chronic idiopathic urticaria:**
* 6 months to 11 years: 30 mg orally twice daily.
* 12 years and older: 180 mg orally once daily (same as adult).
## Dose Adjustments
* **Renal Impairment:** No dose adjustment is typically needed based on creatinine clearance. However, caution is advised and consideration for reducing the dose may be warranted per clinical judgment.
* **Hepatic Impairment:** No dose adjustment is typically needed.
## Contraindications
* Hypersensitivity to fexofenadine or any component of the formulation.
## Adverse Effects
* Headache
* Dizziness
* Nausea
* Fatigue
## Key Drug Interactions
* **Aluminum and magnesium-containing antacids:** May decrease fexofenadine absorption. Separate administration by at least 2 hours.
* **Fruits rich in tannins (e.g., grapefruit, orange, apple):** May decrease fexofenadine absorption. Caution advised.
## Monitoring
* Assess for symptom relief (nasal congestion, sneezing, itching, rhinorrhea, urticaria).
* Monitor for adverse effects, particularly dizziness and fatigue.
## Clinical Pearls
* Fexofenadine is considered non-sedating.
* Onset of action is typically within 1 hour, with peak effects at 2.5 hours.
* It is important to counsel patients to avoid co-administration with antacids and certain fruit juices to ensure optimal efficacy.
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**Disclaimer:** This information is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional and refer to the most current prescribing information for any medication.
