Sedative Effects of Levocetirizine: A Systematic Review and Meta-Analysis of Randomized Controlled Studies

Introduction As a substrate of P-glycoprotein, levocetirizine should not cause sedative effects. However, while cetirizine, a mixture of levocetirizine and dextrocetirizine, can slightly penetrate the blood brain barrier, the sedative effects of levocetirizine are still under study. Objectives The aim of this study was to investigate the sedative effects of levocetirizine. Methods An electronic literature search was performed using Medline and EMBASE from January 01, 2001 through August 6, 2015. Randomized controlled trials (RCTs) comparing levocetirizine with other antihistamines or placebo for patients with allergy and healthy subjects were selected. Primary outcome was risk ratio between levocetirizine and comparators. Secondary outcome was change in psychomotor speed. Data were pooled for meta-analysis using a fixed-effect model. Results Forty-eight studies of 18,014 patients met the inclusion criteria. When compared to placebo, levocetirizine produced modest sedative effects (RR: 1.67; 95% CI 1.17, 2.38). However, when compared to other second-generation antihistamines, sedative effects of levocetirizine did not differ (RR: 1.23; 95% CI 0.96, 1.58). In subgroup analysis, there was no difference between the sedative effects of levocetirizine and fexofenadine (RR: 1.7; 95% CI 0.59, 4.88), desloratadine (RR: 1.58; 95% CI 0.9, 2.77), loratadine (RR: 1.56; 95% CI 0.28, 8.56), bilastine (RR: 1.17; 95% CI 0.48, 2.84), olopatadine (RR: 1.09; 95% CI 0.81, 1.47), azelastine (RR: 0.19; 95% CI 0.01, 3.68) and rupatadine (RR: 1.47; 95% CI 0.14, 15.72). When compared to first-generation antihistamines, levocetirizine had less sedative effects and less change of reaction time (mean difference: -250.76 s; 95% CI -338.53, -162.98). Conclusion Levocetirizine has modest sedative effects with a risk ratio of 1.67 when compared with placebo. The sedative effects observed for levocetirizine are not different from other second-generation antihistamines.