Summary of the more commonly used H(1)-antihistamines licensed for use in children
| First-generation H(1)-antihistamines | The most common adverse effect of the first-generation H(1)-antihistamines is central nervous system depression, with effects varying from slight drowsiness to deep sleep. Paradoxical stimulation may occasionally occur, especially at high doses. These sedative effects, when they occur, may diminish after a few days of treatment. Other first-generation H(1)-antihistamine side effects include headache, psychomotor impairment and anti-muscarinic effects, such as dry mouth, thickened respiratory-tract secretions, blurred vision, urinary difficulty or retention, constipation and increased gastro-oesophageal reflux. Other rare side effects of first-generation H(1)-antihistamines include hypotension, palpitation, arrhythmias, extrapyramidal effects, dizziness, confusion, depression, sleep disturbances, tremour, convulsions, hypersensitivity reactions (including bronchospasm, angio-oedema, anaphylaxis, rashes, and photosensitivity reactions), blood disorders and liver dysfunction. | ||||
| Proprietary forms | Availability | Licensed indication | Licensing age | Children's dose1 (oral doses) | |
|---|---|---|---|---|---|
| Chlorphenamine (Chlorpheniramine) | Non-proprietary Piriton Allerief | P GSL | Symptomatic relief of allergy such as hay fever, urticaria, food allergy, drug reactions, relief of itch associated with chickenpox | Liquid 1–18 years Tabs 6–18 years | 1 month–2 years 1 mg twice daily 2–6 years 1 mg every 4–6 h, max. 6 mg daily 6–12 years 2 mg every 4–6 h, max. 12 mg daily 12–18 years 4 mg every 4–6 h, max. 24 mg daily |
| Hydroxyzine | Atarax Ucerax | POM | Pruritus | 1–18 years | 6 months–6 years initially 5–15 mg at night, increased if necessary to 50 mg daily in 3–4 divided doses 6–12 years initially 15–25 mg at night, increased if necessary to 50–100 mg daily in 3–4 divided doses 12–18 years initially 25 mg at night, increased if necessary to 100 mg in 3–4 divided doses |
| Ketotifen | Zaditen eye drops—Zaditen | POM POM | Symptomatic relief of allergy, such as allergic rhinitis (AR) eye drops—seasonal allergic conjunctivitis | 3–18 years 3–18 years | 3–18 years 1 mg twice daily 3–18 years apply twice daily |
| Promethazine hydrochloride | Non-proprietary Phenergan | POM | Symptomatic relief of allergy, such as hay fever, insomnia associated with urticaria and pruritus | 2–18 years | 2–5 years 5 mg twice daily or 5–15 mg at night 5–10 years 5–10 mg twice daily or 10–25 mg at night 10–18 years 10–20 mg 2–3 times daily or 25 mg at night increased to 25 mg twice daily if necessary |
| Second-generation H(1)-antihistamines | Generally, the second-generation H(1)-antihistamines have little or no side effect of drowsiness or antimuscarinic effect. | ||||
| Cetirizine | Non-proprietary Piriteze Benadryl for children | GSL P POM | Hay fever, chronic idiopathic urticaria, atopic eczema | 2–18 years | 1–2 years 250 µg/kg twice daily 2–6 years 2.5 mg twice daily 6–12 years 5 mg twice daily 12–18 years 10 mg once daily |
| Loratadine | Non-proprietary Loratadine Allereze, Clarityn | GSL P POM | Symptomatic relief of allergy, such as hay fever, chronic idiopathic urticaria | 2–18 years | 2–12 years under 30 kg 5 mg once daily over 30 kg 10 mg once daily 12–18 years 10 mg once daily |
| Fexofenadine | Non-proprietary Telfast | POM | Symptomatic relief of seasonal AR symptomatic relief of chronic idiopathic urticaria | 6–18 years | 6–12 years 30 mg twice daily 12–18 years 120 mg once daily 12–18 years 180 mg once daily |
| Levocetirizine | Xyzal | POM | Symptomatic relief of allergy, such as hay fever, urticaria | Liquid 2–18 years Tablets 6–18 years | 2–6 years 1.25 mg twice daily 6–18 years 5 mg once daily |
| Desloratadine | Desloratadine (non-proprietary). Neoclarityn | POM | Hay-fever, chronic idiopathic urticaria | 1–18 years | 1–6 years 1.25 mg once daily 6–12 years 2.5 mg once daily 12–18 years 5 mg once daily |
| Olopatadine | Opatanol | POM | Seasonal allergic conjunctivitis | 3–18 years | Child 3–18 years apply twice daily; max. duration of treatment 4 months |
| Acrivastine | Non-proprietary Acrivastine. Benadryl allergy relief | GSL P POM | Hay fever, chronic idiopathic urticaria | 12–18 years | 8 mg three times a day |
| Azelastine | Optilast Rhinolast Dymista—with fluticasone | POM POM POM | Allergic conjunctivitis, seasonal allergic conjunctivitis Perennial conjunctivitisSeasonal and perennial AR Moderate to severe seasonal and perennial AR, if monotherapy with antihistamine or corticosteroid is inadequate | 4–18 years 5–18 years 12–18 years | Child 4–18 years apply twice daily, increased if necessary to 4 times daily Child 12–18 years apply twice daily, increased if necessary to 4 times daily; max. duration of treatment 6 weeks 1 spray into each nostril twice daily Child 12–18 years 1 spray into each nostril twice daily |
Availability based on UK licensing includes whether on prescription (POM), or over the counter medicines: including pharmacist only (P) and general sales list medicines (GSL), which varies depending on license, pack size and brands. The licensed age range also varies from brand to brand. The usual dosing for various age ranges is described at the time of publication. The Table comprises information from summary of product characteristics for each H(1)-antihistamine and other source references.10 ,48 ,49