Please check your internet connection and try again.
# Allegra (fexofenadine)
## Overview
Fexofenadine is a second-generation, selective H1-receptor antagonist. It is a carboxylic acid metabolite of terfenadine that does not cross the blood-brain barrier significantly, resulting in a non-sedating profile.
## Primary Indications
- Seasonal Allergic Rhinitis (SAR)
- Chronic Idiopathic Urticaria (CIU)
## Adult Dosing
- **Allergic Rhinitis:** 60 mg twice daily OR 180 mg once daily.
- **Chronic Idiopathic Urticaria:** 60 mg twice daily.
## Pediatric Dosing
*Note: Not for use in children < 6 months old.*
- **Children 6 months to < 2 years:** 15 mg orally twice daily (Oral Suspension).
- **Children 2 to < 12 years:** 30 mg orally twice daily (Oral suspension or orally disintegrating tablets).
- **Children ≥ 12 years:** Same as adult dosing.
## Dose Adjustments
- **Renal Impairment:** Reduce starting dose to 60 mg once daily for patients with creatinine clearance < 80 mL/min (refer to product labeling for specific titration).
- **Hepatic Impairment:** No official dosage adjustment required.
## Contraindications
- Hypersensitivity to fexofenadine or any component of the formulation.
## Adverse Effects
- **Common:** Headache, nausea, dizziness, dysmenorrhea, upper respiratory tract infection.
- **Rare but serious:** Hypersensitivity reactions (urticaria, angioedema, chest tightness, dyspnea).
## Key Drug Interactions
- **Aluminum/Magnesium Antacids:** May decrease fexofenadine absorption; separate administration by at least 2 hours.
- **Fruit Juices (Grapefruit, Orange, Apple):** May significantly decrease fexofenadine bioavailability via inhibition of organic anion transporting polypeptides (OATPs). Avoid consuming around the time of dosing.
- **Erythromycin/Ketoconazole:** May increase fexofenadine plasma concentrations (likely due to P-gp inhibition), though clinical significance is generally minor.
## Monitoring
- Monitor for the resolution of allergic symptoms or hives.
- Monitor for signs of hypersensitivity.
- No routine laboratory monitoring is required.
## Clinical Pearls
- Fexofenadine is considered one of the least sedating antihistamines available.
- Unlike first-generation antihistamines, it provides minimal to no anticholinergic effects.
- If using orally disintegrating tablets, ensure the patient allows the tablet to dissolve on the tongue before swallowing.
- Efficacy may be reduced if taken with fruit juice; water is the preferred beverage for administration.
***
*Disclaimer: This information is for educational purposes only. Clinical practice guidelines and dosing may vary; always verify current prescribing information, package inserts, and institution-specific protocols before administration.*
