Least sedating second generation antihistamine
None of the second-generation antihistamines marketed in the United States displays this precaution. Our aim, therefore, was to compare the sedating effects of a second-generation antihistamine, cetirizine, and the first-generation chlorpheniramine with placebo in school-going children with allergic rhinitis using the P300 event-related potential (ERP) as an objective neurophysiological test.Also, cetirizine overdose in children is more likely to cause sedation than overdose with the other second-generation antihistamines. The visual analog scale (VAS) was used to measure subjective sleepiness or somnolence.
First- and second-generation antihistamines show varying degrees of sedation, but to date, objective studies in children are lacking.On each study day, the children would arrive at the hospital between after taking breakfast.The study day would be postponed if there were: 1) hospitalization or acute illness within the last 2 weeks; 2) use of antihistamines or any other medications that may affect CNS function in the last 2 weeks; 3) presence of signs or symptoms of asthma or atopic dermatitis; or 4) consumption of dietary items that may contain methylxanthines, such as cola drinks, coffee, or chocolate in the 24 hours before the study.Chlorpheniramine and cetirizine increased P300 latency when compared with baseline. The significant increase in P300 latency was not accompanied by significant change in subjective somnolence as measured by the visual analog scale.We have shown that cetirizine has sedative properties in children.Antihistamines are classified into two groups – the first-generation (“sedating”) and second-generation (“non-sedating”).Sedating antihistamines cause sedation as they are highly lipid soluble and readily cross the blood brain barrier.Their large molecular size and greater affinity for peripheral H1 receptors also reduce their propensity to cause sedation.Recent studies have shown that the poorer affinity of these newer antihistamines for the P-glycoprotein efflux pump at the blood-brain barrier may also explain their relative lack of central nervous system (CNS) side effects.Twenty-four children aged 7 to 14 years with allergic rhinitis completed the study.All children were randomly allocated to medication sequences and received 3 different drugs on 3 different days, at least 1 week apart.