THE PHENOMENON OF SEVERE REBOUND PRURITUS FOLLOWING CETIRIZINE AND LEVOCETIRIZINE DISCONTINUATION: A SYSTEMIC ANALYSIS OF CURRENT EVIDENCE AND JUSTIFICATION OF A NEW PATHOGENETIC CONCEPT AND CORRECTION TACTICS

Background. Second-generation H1-antihistamines, such as cetirizine and levocetirizine, are widely used drugs of choice for the treatment of allergic diseases due to their high selectivity and safety. However, in recent years, clinical practice and pharmacovigilance systems (FDA) have accumulated data on a specific phenomenon — the occurrence of severe pruritus developing after the discontinuation of these drugs. In domestic literature, this withdrawal syndrome is virtually undescribed, which may lead to misdiagnosis of the underlying disease relapse.

Aim. To conduct a comprehensive analysis of available data on the prevalence, clinical presentation, and onset timing, to develop a pathogenetic model, and to justify management algorithms for recurrent pruritus after cetirizine and levocetirizine withdrawal.

Materials and Methods. An information search was conducted in international and Russian databases (PubMed/MEDLINE, Google Scholar, Scopus, eLibrary, and RSCI), official regulatory sources (FDA, GRLS), and open information networks (Google, Yandex) without language or time restrictions. Conceptual modeling was used to synthesize a pathogenetic hypothesis based on the analysis of clinical data, pharmacodynamics and pharmacokinetic parameters of the drugs.

Results. The clinical features of the syndrome were systematized: onset within 1–5 days after discontinuation, distressing generalized pruritus, and a lack of correlation with the underlying disease. The assumption of significant underdiagnosis of this condition was formulated. An original pathogenetic concept was developed, explaining the withdrawal syndrome through the mechanism of compensatory hypersensitization of H1-receptor cascades during prolonged blockade. Management strategies for recurrent pruritus were proposed and justified, including symptom relief by resuming cetirizine or levocetirizine, a gradual dose tapering method, and therapeutic rotation to an antihistamine with different pharmacokinetic parameters.

Conclusion. Recurrent pruritus following cetirizine withdrawal is a predictable pharmacodynamic effect. Understanding the mechanisms of receptor adaptation allows for optimizing the strategy for therapy completion, avoiding unnecessary systemic drug administration, and improving patient quality of life.