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 |
| Molecular Weight | 501.77 |
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 | Limited human data; animal studies not available. Fexofenadine is generally considered low risk but use only if clearly needed. |
| 2nd trimester | No known harm; preferred antihistamine due to lack of anticholinergic effects. Use if benefit outweighs risk. |
| 3rd trimester | No known harm; preferred antihistamine. Avoid near term due to theoretical risk of neonatal irritability or sedation. |
Clinical note
Comprehensive clinical and safety monograph for CHILDREN'S ALLEGRA HIVES (CHILDREN'S ALLEGRA HIVES).
| Placental transfer | Fexofenadine crosses the placenta in animal studies; limited human data suggest minimal transfer. It is a P-gp substrate, limiting fetal exposure. |
| Breastfeeding | Fexofenadine is excreted into breast milk in low amounts; infant doses are subclinical. It is considered compatible with breastfeeding. Monitor infant for drowsiness or irritability. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to fexofenadine or any component of the formulation
| 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 |
Loading safety data…
| Lactation Rating | L2 (Safer) |
| 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. |
| 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. |