Indications

Allergic Rhinitis: Alerfast is indicated for the relief of symptoms associated with seasonal and perennial allergic rhinitis in adults and children aged 12 years and above. Symptoms effectively treated include sneezing, rhinorrhea, lacrimation, itchy or red eyes, and itching of nose/palate/throat. Alerfast improves health-related quality of life and work/activity productivity.

Chronic Idiopathic Urticaria: Alerfast is indicated for the relief of symptoms associated with chronic idiopathic urticaria in adults and children aged 12 years and above. It significantly reduces the number and severity of wheals and pruritus, improving health-related quality of life and productivity.

Pharmacology

Histamine H1 receptors mediate hypersensitivity and allergic reactions. Exposure to allergens causes mast cell and basophil degranulation, releasing histamine and other inflammatory mediators. Histamine binds to H1 receptors, triggering further release of pro-inflammatory cytokines such as interleukins. These downstream effects lead to allergic symptoms like itching, rhinorrhea, and watery eyes.

Fexofenadine acts as an inverse agonist at H1 receptors, stabilizing them in an inactive state and preventing activation. It has potent and selective affinity for H1 receptors without dopaminergic, serotonergic, cholinergic, or adrenergic blocking activity. Fexofenadine does not cross the blood–brain barrier, minimizing central nervous system effects.

Dosage & Administration

Allergic Rhinitis:

Adults & children ≥12 years: 60 mg twice daily or 120 mg once daily or 180 mg once daily.
- Renal impairment: 60 mg once daily.
Children 6–11 years: 30 mg twice daily or 60 mg once daily.
- Renal impairment: 30 mg once daily.
Children 2–5 years: Suspension 30 mg (5 mL) twice daily.
- Renal impairment: 30 mg (5 mL) once daily.

Chronic Idiopathic Urticaria:

Adults & children ≥12 years: 60 mg twice daily or 120 mg once daily or 180 mg once daily.
- Renal impairment: 60 mg once daily.
Children 6–11 years: 30 mg twice daily or 60 mg once daily.
- Renal impairment: 30 mg once daily.
Children 6 months–2 years: Suspension 15 mg (2.5 mL) twice daily.
- Renal impairment: 15 mg (2.5 mL) once daily.
Children 2–5 years: Suspension 30 mg (5 mL) twice daily.
- Renal impairment: 30 mg (5 mL) once daily.

Interaction

Alerfast does not undergo hepatic metabolism and thus has minimal drug interactions. Co-administration with erythromycin or ketoconazole increases plasma fexofenadine levels 2–3 times, without QT interval changes or adverse effects. No interaction with omeprazole observed. Antacids containing aluminum or magnesium hydroxide reduce bioavailability if taken within 15 minutes; maintain a 2-hour gap between Alerfast and such antacids.

Contraindications

Contraindicated in patients with known hypersensitivity to Fexofenadine Hydrochloride or any component of the formulation.

Side Effects

Common: Headache, drowsiness, dizziness, nausea. Uncommon: Fatigue. Rare/Unknown: Hypersensitivity reactions (angioedema, chest tightness, dyspnea, flushing, systemic anaphylaxis), insomnia, nervousness, sleep disturbances, tachycardia, palpitations, diarrhea, rash, urticaria, pruritus.

Pregnancy & Lactation

No adequate data in pregnant women. Animal studies show no direct or indirect harmful effects. Use only if clearly necessary. Fexofenadine may pass into breast milk; therefore, not recommended for breastfeeding mothers. No evidence of fertility impairment in animal studies.