Adult and adolescent > 12 years
Stage 2 / second-line treatment

Back to decision-making tree Print last updated on 21/02/2024

Increased dose of second-generation anti-H1 antihistamines
up to 4 doses per day

Increasing the dose by a factor of 4 has shown good results with cetirizine and levocetirizine, providing better symptom control than the conventional dose.

The dose increase should be rapid (< 2 months) as efficacy is demonstrated in the short term: the time before increasing the dose depends on the study, ranging from 1 week to 2 months. The manner in which the dose is increased is not uniform across studies, where it is most often increased incrementally.

Most experts, in case of resistance to conventional doses of anti-H1 antihistamines, use a quadruple dose of anti-H1 antihistamines right away, then decrease to 3 doses, then 2 or even 1 after achieving remission at the minimum effective dose.

With regard to the tolerance of cetirizine, levocetirizine and rupatadine, no more frequent or more serious adverse effects were found at higher doses than at conventional dose. The main adverse effects are drowsiness, including with second-generation anti-H1 drugs, headache and nausea.

• Cetirizine and levocetirizine are the treatments for which the most data are available.
• In studies, dose increases were gradual, from 1 dose to 2, then 3, then 4, with delays ranging from 1 week to 1 month between each step.
• Most experts, however, proceed directly from 1 dose to 4, then gradually decrease dose-by-dose once clinical remission is achieved, in order to find the minimum effective dose.
• There are no data on the distribution of a quadruple dose during the day. Most experts suggest 2 doses in the morning and 2 in the evening.

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