Assessment of Different Cetirizine Dosing Strategies on Seasonal Allergic Rhinitis Symptoms: Findings of Two Randomized Trials.

BACKGROUND: Cetirizine has been shown to be effective for relief of seasonal allergic rhinitis (SAR) symptoms. Allergic rhinitis symptoms have been reported to have circadian variations, with symptoms tending to be most bothersome overnight and in the morning. OBJECTIVE: To evaluate the effects of different cetirizine dosing schedules in comparison to twice daily (BID) chlorpheniramine and placebo on SAR symptoms at 12 and 24 hours postdose. METHODS: Study 1 subjects received cetirizine 10-mg once daily in the morning (QAM), cetirizine 10-mg once daily at bedtime (QHS), cetirizine 5-mg twice daily, or placebo. Study 2 subjects received cetirizine 5-mg QAM, cetirizine 10-mg QHS, chlorpheniramine 8-mg BID, or placebo. The primary end point was total symptom severity complex (TSSC); TSSC was the sum of symptom severity ratings averaged over the 2-week study period. Post hoc analyses of reflective symptom severity assessed in the morning (TSSCAM) and in the evening (TSSCPM) were conducted to evaluate cetirizine's effects at 12 and 24 hours postdose. RESULTS: In study 1, subject- and investigator-assessed TSSC was significantly lower in all cetirizine groups versus placebo (P ≤ .003). In study 2, subject-assessed TSSC was significantly lower in all cetirizine groups versus placebo (P ≤ .04) and was numerically lower for investigator-assessed TSSC. Post hoc analyses demonstrated that cetirizine significantly improved TSSCAM at 12 and 24 hours postdose versus placebo in both studies regardless of dosing schedule. TSSCPM significantly improved at 12 and 24 hours postdose in all study 1 cetirizine groups versus placebo. In study 2, versus placebo, TSSCPM significantly improved at 12 hours postdose in cetirizine 5-mg QAM group and numerically improved at 24 hours postdose in cetirizine 10-mg QHS group. CONCLUSION: Regardless of dosing regimen, cetirizine demonstrates effective 24-hour relief of SAR symptoms, particularly on TSSCAM, which assesses overnight and early morning symptom control.

Randomized, placebo-controlled study of cetirizine and loratadine in children with seasonal allergic rhinitis.

BACKGROUND: Pharmacologic treatment is a mainstay of allergy therapy and many caregivers use over-the-counter antihistamines for the treatment of seasonal allergic rhinitis (SAR) symptoms in children. OBJECTIVE: To assess the efficacy and safety of cetirizine 10 mg syrup versus loratadine 10 mg syrup versus placebo syrup in a randomized double-blind study of children, ages 6-11 years, with SAR. METHODS: This randomized, double-blind, parallel-group, placebo-controlled study was conducted at 71 U.S. centers during the spring tree and grass pollen season. After a 1-week placebo run-in period, qualified subjects were randomized to once-daily cetirizine 10 mg (n = 231), loratadine 10 mg (n = 221), and placebo (n = 231) for 2 weeks. The primary efficacy end point was change from baseline in the subject's mean reflective total symptom severity complex (TSSC) score over 14 days. RESULTS: Children treated with cetirizine experienced significantly greater TSSC score reductions versus children treated with placebo over 14 days (least square mean change, -2.1 versus -1.6; p = 0.006). The differences in TSSC score improvement over 14 days between the cetirizine versus loratadine groups (-2.1 versus -1.8; p = 0.124) and between the loratadine versus placebo groups (-1.8 versus -1.6; p = 0.230) were not statistically significant. Predominant adverse events in the cetirizine, loratadine, and placebo groups were headache (3.5, 3.6, and 3.1%, respectively) and pharyngitis (3.5, 2.7, and 3.5%, respectively). Somnolence was reported in three subjects (1.3%) treated with cetirizine and in none of the other subjects. CONCLUSION: Cetirizine 10 mg was statistically significantly more efficacious than placebo in the treatment of SAR symptoms in children ages 6-11 years. Symptom improvement was not significantly different between the loratadine 10 mg and placebo groups.

Effect of cetirizine on symptom severity and quality of life in perennial allergic rhinitis.

The effect of cetirizine on quality of life (QOL) in subjects with perennial allergic rhinitis (PAR) has been previously evaluated using generic instruments. While generic QOL tools are used across various conditions, disease-specific instruments evaluate the impact of treatment on areas that are affected by that particular condition. This study evaluated the effect of cetirizine on symptom severity and health-related QOL, using a disease-specific instrument, in adults with PAR. This randomized, double-blind, placebo-controlled study was conducted at 15 U.S. centers outside the pollen allergy season. After a 1-week placebo run-in period, qualified subjects aged 18-65 years with PAR were randomized to once-daily cetirizine 10 mg (n = 158) or placebo (n = 163) for 4 weeks. Change from baseline in total symptom severity complex (TSSC) and overall Rhinitis Quality of Life Questionnaire (RQLQ) scores were primary efficacy end points. Cetirizine produced significantly greater improvements in mean TSSC for each treatment week (p < 0.05) and for the entire 4-week treatment period (p = 0.005) compared with placebo. After 4 weeks, cetirizine-treated subjects reported significantly greater overall improvement in RQLQ scores compared with placebo-treated subjects (p = 0.004). After 1 week, cetirizine produced significant improvements in the nasal symptoms, practical problems, and activities RQLQ domain scores compared with placebo (p < 0.05). After 4 weeks, cetirizine-treated subjects reported significant reductions in these RQLQ domain scores and in emotion domain scores compared with placebo-treated subjects (p < 0.05). Cetirizine 10 mg daily produced significant improvements in symptom severity and allergic rhinitis-related QOL compared with placebo in adults with PAR.