Consistency and efficacy of cetirizine (10 mg) versus ebastine (20 mg) at 4 h on skin reactivity
- Cite this article as:
- Purohit, A., Duvernelle, C., Melac, M. et al. E J Clin Pharmacol (1999) 55: 589. doi:10.1007/s002280050677
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Objective: We compared the consistency and efficacy of the two antihistamines, cetirizine (10 mg) and ebastine (20 mg) on histamine skin reactivity 4 h after treatment.
Methods: Twenty-four healthy volunteers participated in a randomised double-blind cross-over study. The areas of wheals and flares induced by increasing (0, 5, 10, 50, 100, 200, 300 mg/ml) histamine concentrations, administered by prick tests, were measured before and 4 h after intake of cetirizine or ebastine.
Results: Before treatment, concentration–response curves were similar and threshold concentrations identical (0.57 mg/ml and 0.57 mg/ml for cetirizine and ebastine, respectively). Both treatments exerted a significant effect. However, cetirizine was significantly more efficient than ebastine 20 mg (P < 0.01 both for wheals and flares). After cetirizine, the threshold concentration inducing a 3-mm2 wheal was significantly higher (266 mg/ml) than after ebastine (77 mg/ml) (P < 0.01), and total inhibition of the wheal was obtained in 18 of 24 patients for cetirizine and in 4 of 24 for ebastine (P < 0.001). The variation coefficient for the wheal reaction was 31% for cetirizine and 159% for ebastine, indicating a much lower variability after cetirizine.
Conclusion: Our study shows clearly that the efficacy of a single therapeutic dosage of cetirizine is greater and consistently better than that of ebastine for suppression of cutaneous reactivity to histamine 4 h after treatment in healthy volunteers. The need for ebastine to metabolise into the active carebastine might explain this difference.