What is the recommended dose and duration of levocetirizine (antihistamine) for treating generalized itching?

Levocetirizine Dosing for Generalized Itching

For generalized itching, levocetirizine should be administered at a dose of 5 mg once daily in the evening for adults and children 12-64 years of age, for a duration of 1-2 weeks. 1

Dosing Recommendations

Adults and Children 12-64 years:

• Standard dose: 5 mg once daily in the evening
• For less severe symptoms: 2.5 mg once daily in the evening may be appropriate
• Maximum dose: Do not exceed 5 mg in 24 hours

Children 6-11 years:

• 2.5 mg once daily in the evening
• Do not exceed 2.5 mg in 24 hours

Special Populations:

• Adults 65 years and older: Consult a doctor before use
• Children under 6 years: Not recommended
• Patients with kidney disease: Not recommended

Duration of Treatment

For generalized pruritus of unknown origin (GPUO), a short course of 1-2 weeks is typically sufficient to manage symptoms. The British Association of Dermatologists recommends non-sedating antihistamines such as levocetirizine as a treatment option for GPUO 2.

Treatment Algorithm for Generalized Itching

1. First-line approach:

   • Levocetirizine 5 mg once daily in the evening
   • Combine with emollients and self-care advice 2

2. If incomplete relief after 3-5 days:

   • Consider combination therapy with H2 antagonists (e.g., cimetidine) 2
   • Do not increase levocetirizine beyond recommended dose due to risk of sedation 2, 1

3. If still inadequate response after 1-2 weeks:

   • Refer to secondary care for further evaluation and management 2
   • Consider alternative treatments such as topical doxepin, menthol, or clobetasone butyrate 2

Important Considerations

• Levocetirizine is preferred over sedating antihistamines, especially in elderly patients, as sedating antihistamines may increase risk of dementia with long-term use 2, 3
• Monitor for adverse effects, particularly sedation, which occurs more frequently at higher doses 4
• Quality of life improvements should be assessed alongside symptom reduction 3
• Avoid prolonged use without reassessment of the underlying cause of pruritus 2

Cautions and Contraindications

• Do not use in patients with severe renal impairment 1
• Use with caution in elderly patients due to potential for increased side effects 1
• Be aware of potential for fixed drug eruptions with levocetirizine, particularly in patients with history of drug reactions 5

Remember that generalized pruritus may be a symptom of underlying conditions requiring specific treatment. If symptoms persist beyond the initial treatment period, further investigation is warranted to identify and address the root cause.