Levocetirizine is effective for symptom relief including nasal congestion in adolescent and adult (PAR) sensitized to house dust mites

BACKGROUND: Antihistamines are the most commonly prescribed class of medication for perennial allergic rhinitis (PAR). The primary objective of this study was to determine whether levocetirizine (Xyzal(R)), the active enantiomer of cetirizine, could achieve at least a 50% improvement in PAR symptoms compared to the placebo over the first week of treatment. METHODS: A total of 294 patients with PAR due to house dust mites were randomized in this 8-week double-blind, placebo-controlled, multicentre trial to receive either levocetirizine 5 mg/day or placebo. Mean Total Four-Symptom Scores (T4SS) (nasal pruritus, ocular pruritus, rhinorrhoea and sneezing) were compared between treatment groups over weeks 1, 4 and 6. All individual symptom scores, including nasal congestion, were also studied. RESULTS: Levocetirizine showed an 86% improvement in T4SS over the first week of treatment and a 47% improvement over the entire treatment period compared with placebo. Absolute changes from baseline were 3.64 and 2.47 for levocetirizine and placebo, respectively. Individual symptom scores showed statistically significant (P < or = 0.01) differences in favour of levocetirizine for all study time-points. Nasal congestion was unexpectedly significantly improved (P < 0.001). The incidence of reported adverse events was comparable between treatment and placebo group. CONCLUSIONS: Levocetirizine 5 mg/day is an effective and well-tolerated treatment of PAR. In addition, levocetirizine is effective for the relief of nasal congestion.