Cognitive impairment under treatment with second‐ and third‐generation antihistamines

Abstract

AbstractBackgroundBrain histamine is involved in the regulation of arousal, cognition, and memory mainly through interactions with histamine H1 receptors. Histamine H1 antagonists often prescribed for treatment of allergic disorders, may induce sleepiness and cognitive deficits. Sedation as a consequence of treatment with 1st generation antihistamines has led to the development of 2nd and 3rd generation anthistamines, which are thought to be free of cognitive side effects. This proved to be true in studies on the cognitive effects of single doses in healthy volunteers. However, the relationship between treatment with 2nd or 3rd generation antihistamines and cognitive performance so fas has not been examined within a naturalistic study under everyday conditions. This may be relevant for Alzheimer’s disease treatment studies, because cognitive side effects as a consequence of treatment with 2nd or 3rd generation antihistamines may act as a confounding variable.Method380 patients with chronic spontaneous urticaria (CSU) were assessed in 30 dermatological practices and outpatient clinics in Germany. Severity of disease was assessed by means of the Urticaria Activity Score (UAS‐7) and the Urticaria Control Test (UCT), quality of life by the Dermatology Life Quality Index (DLQI) and the Chronic Urticaria Quality of Life Questionnaire (CU‐Q2oL). Cognitive performance was studied by means of the computer‐based Memory and Attention Test (MAT). Sociodemographic data, current medication in treatment categories, comorbidities, obesity, smoking and drinking habits are taken by a questionnaire.ResultThe assessments were carried out in 380 subjects at ages between 19 and 73 years (mean +/‐ SD: 49 +/‐ 15). In patients under treatment with 2nd or 3rd generation anthistamines compared to patients not under treatment with antihistamines, we found a significant impairment of episodic working memory, particularly in the elder subjects. The impairment was found independently whether antihistamines were applied at dosages licensed for treatment or at higher dosages. Episodic short‐term memory and selective attention were unimpaired.ConclusionTreatment with 2nd or 3rd generation antihistamines may be associated with cognitive impairment, particularly in elderly patients. This effect should be considered regarding the handling of concomitant medications in Alzheimer’s disease treatment trials.