What is the recommended dosing and administration of bilastine for allergic rhinitis and chronic spontaneous urticaria in adults and children ≥ 12 years, and what are its contraindications, common adverse effects, drug interactions, and alternative antihistamines?

Bilastine for Allergic Rhinitis and Chronic Spontaneous Urticaria

Recommended Dosing and Administration

Bilastine should be dosed at 20 mg once daily in adults and adolescents ≥12 years, and 10 mg once daily in children aged 6 to <12 years for both allergic rhinoconjunctivitis and urticaria. 1, 2

Critical Administration Requirements

• Take bilastine at least 1 hour before or 2 hours after food or fruit juice, as absorption is significantly slowed when taken with meals 3
• This timing requirement is essential for optimal efficacy and must be emphasized to patients 3

Age-Specific Dosing

• Adults and adolescents ≥12 years: 20 mg once daily 4, 1
• Children 6 to <12 years: 10 mg once daily 1, 2
• Children <6 years: Not approved; insufficient safety and efficacy data 2

Special Populations

• No dose adjustment required in renal impairment, hepatic impairment, or elderly patients 4, 1
• This represents a significant practical advantage over many other antihistamines 4

Contraindications

Bilastine is contraindicated only in patients with hypersensitivity to bilastine or any component of the formulation. 4, 1

• No other absolute contraindications exist, making it suitable for patients with renal or hepatic disease 4, 1

Common Adverse Effects

Bilastine demonstrates minimal sedative properties and is generally well tolerated even at supratherapeutic doses. 4, 1

Safety Profile

• Sedation rates are lower than other second-generation antihistamines including cetirizine 4
• No anticholinergic effects (no dry mouth, constipation, or urinary retention) 1
• No cardiotoxicity or QT prolongation 4, 1
• Minimal central nervous system penetration 1
• Well tolerated at doses up to 4-fold higher than standard (80 mg daily) for refractory urticaria 4

Most Common Side Effects

The incidence of adverse events with bilastine 20 mg (20.6%) is comparable to placebo (18.8%) 5

Drug Interactions

Bilastine has exceptionally low potential for drug-drug interactions because it does not undergo significant metabolism and does not interact with the cytochrome P450 system. 4, 1

Key Interaction Considerations

• Does not undergo hepatic metabolism—excreted largely unchanged 4
• No CYP450 interactions, unlike many other antihistamines 1
• Avoid concurrent administration with food or fruit juice (pharmacokinetic interaction reducing absorption) 3

Clinical Efficacy

Bilastine demonstrates efficacy comparable to cetirizine and desloratadine for seasonal allergic rhinitis, with rapid onset and prolonged duration of action. 4, 5

Comparative Effectiveness

• Non-inferior to desloratadine 5 mg for total symptom scores in seasonal allergic rhinitis 5
• Similar efficacy to cetirizine in perennial allergic rhinitis and chronic spontaneous urticaria 4
• Potentially longer duration of action than fexofenadine in chamber studies 4
• Effective for all nasal symptoms including obstruction, contrary to older beliefs about antihistamines 3
• Improves both nasal and ocular symptoms, as well as quality of life 5

Onset and Duration

• Rapid onset of action with prolonged duration 4, 1
• Suitable for once-daily dosing 1

Alternative Antihistamines

When bilastine is not available or suitable, consider these evidence-based alternatives:

Second-Generation Oral Antihistamines

For adults and children ≥6 years, cetirizine 10 mg once daily or desloratadine 5 mg once daily are appropriate alternatives. 6, 5

• Cetirizine 10 mg once daily (ages ≥6 years); 5 mg once daily (ages 2-5 years) 6

  • More sedating than bilastine, fexofenadine, loratadine, or desloratadine 6
  • Requires dose reduction in moderate renal impairment (5 mg daily) 6
  • Avoid in severe renal impairment 6

• Desloratadine 5 mg once daily (comparable efficacy to bilastine) 5

First-Line Treatment Hierarchy

However, intranasal corticosteroids remain more effective than any oral antihistamine for comprehensive symptom control, particularly nasal congestion. 7, 8, 6

• Intranasal corticosteroids (fluticasone, mometasone, triamcinolone) are superior to oral antihistamines for all four major symptoms of allergic rhinitis 8, 6
• Consider intranasal corticosteroids as first-line, with bilastine or other antihistamines for patients who prefer oral therapy or have predominantly sneezing/itching symptoms 8

Important Clinical Caveats

Food Interaction Warning

The most common prescribing error is failing to counsel patients about the food interaction—bilastine must be taken on an empty stomach 3

Pregnancy and Lactation

• Safety data in pregnancy are limited; avoid if possible, especially in first trimester (extrapolating from cetirizine guidance) 6
• Insufficient data on excretion in breast milk 1

Refractory Urticaria

For chronic spontaneous urticaria inadequately controlled with standard dosing, bilastine can be safely increased to 80 mg once daily (4-fold standard dose), which is endorsed in international urticaria guidelines. 4