CHILDREN'S ALLEGRA HIVES
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CHILDREN'S ALLEGRA HIVES (CHILDREN'S ALLEGRA HIVES).
Fexofenadine is a selective peripheral H1-receptor antagonist that blocks histamine-mediated effects, reducing pruritus and urticaria.
| Metabolism | Minimally metabolized; 5% undergoes hepatic metabolism via CYP3A4; majority excreted unchanged in feces and urine. |
| Excretion | Fecal (80% as unchanged drug); renal (15%, mostly as metabolites; <5% unchanged) |
| Half-life | Terminal half-life: 14.4 hours; clinical context: supports twice-daily dosing in chronic urticaria |
| Protein binding | ~60–70% bound to plasma proteins (primarily albumin) |
| Volume of Distribution | 5.5–7.5 L/kg; indicates extensive tissue distribution beyond plasma |
| Bioavailability | Oral: ~40% (first-pass metabolism) |
| Onset of Action | Oral: 1–3 hours for antihistamine effect; peak effect at 6 hours |
| Duration of Action | 24 hours; clinical note: symptom relief from urticaria persists for the dosing interval |
Fexofenadine 180 mg orally once daily for adults and children 12 years and older.
| Dosage form | TABLET, ORALLY DISINTEGRATING |
| Renal impairment | For CrCl < 40 mL/min: 60 mg orally once daily. |
| Liver impairment | No dosage adjustment required for mild to moderate hepatic impairment; not studied in severe impairment. |
| Pediatric use | Children 6 months to <2 years: 15 mg orally twice daily; 2 to <12 years: 30 mg orally twice daily; 12 years and older: 60 mg orally twice daily or 180 mg once daily. |
| Geriatric use | Start at lower end of dosing range due to potential decreased renal function; consider CrCl adjustment if <40 mL/min. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CHILDREN'S ALLEGRA HIVES (CHILDREN'S ALLEGRA HIVES).
| Breastfeeding | Fexofenadine is excreted into human breast milk in low concentrations; the milk-to-plasma ratio is approximately 0.4. Although unlikely to cause adverse effects in nursing infants, caution is advised due to the potential for irritability or sedation. Use only if benefits outweigh risks. |
| Teratogenic Risk | Fexofenadine is classified as FDA Pregnancy Category C. Limited human data; animal studies at doses up to 3 times the maximum recommended human dose (MRHD) showed no teratogenicity. First trimester: insufficient data to assess risk; second and third trimesters: no known fetal risk from reported human experiences. However, antihistamines should be used only if clearly needed. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to fexofenadine or any component","Not for acute asthma exacerbation"]
| Precautions | ["Avoid coadministration with fruit juices (apple, orange, grapefruit) which decrease absorption","Use with caution in patients with hepatic or renal impairment","Not recommended for children under 2 years"] |
| Food/Dietary | Fruit juices (e.g., apple, orange, grapefruit) significantly reduce fexofenadine absorption. Avoid concurrent ingestion. Take with water only. Food does not affect absorption but may delay onset. |
| Clinical Pearls |
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| Fetal Monitoring | No specific maternal-fetal monitoring is routinely required. Monitor for maternal adverse effects such as sedation, dizziness, or dry mouth. If used in pregnancy, assess fetal growth and well-being as part of routine prenatal care, but no special monitoring is indicated. |
| Fertility Effects | In animal studies, fexofenadine did not impair fertility at doses up to 3 times the MRHD. There are no human data on fertility effects; based on available data, fexofenadine is not expected to significantly impact fertility. |
| CHILDREN'S ALLEGRA HIVES contains fexofenadine, a second-generation antihistamine. For pediatric use, dosing is weight-based: 30 mg twice daily for children 2-11 years old. Onset of action is within 1 hour; peak effect at 2-3 hours. It does not cause significant sedation unlike first-generation antihistamines. Avoid in severe renal impairment (CrCl < 30 mL/min). |
| Patient Advice | Take with water, not fruit juices (especially apple, orange, or grapefruit) as they decrease absorption. · Give dose every 12 hours; do not exceed recommended dose. · Shake bottle well before use for liquid formulation. · Store at room temperature away from moisture and heat. · Contact physician if symptoms worsen or fail to improve within 3 days. |