ISSN:
1398-9995
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
It has been speculated whether the recently developed non-sedating antihistamines may possess other properties than merely being antagonists at the H1-receptors. To investigate this suggestion 12 patients with strictly seasonal allergic rhinitis participated in a double-blind placebo controlled randomized cross-over study outside the pollen season. At steady state levels of 10 mg loratadine, a new non-sedating antihistamine, the patients were challenged with methacholine. This was followed by a nasal challenge with increasing doses of allergen. 24 h later the patients were rechallenged nasally with the same methacholine dose as the day before. The volume of the methacholine-induced nasal secretion was measured and the response to allergen was determined by scoring technique. In returned nasal lavage fluid the levels of histamine and TAME-esterase activity were measured. It was found that loratadine significantly reduced the immediate allergic nasal symptoms compared with placebo (P 〈 0.01). Loratadine also reduced the allergen-induced release of histamine into the nasal cavity after the strongest allergen dose, from 9.6±1.5 (mean ± SEM) to 6.4±1.4 ng/ml (P 〈 0.05). A similar decrease in the TAME-esterase activity after treatment with loratadine was observed. The TAME-esterase activity decreased from 11.6 *103±2.47 *103 to 5.60 *103±1.45 */103 CMP (P 〈 0.05). There were no significant changes between the active and placebo treatments regarding the methacholine-induced secretory response. This was true for the initial methacholine challenge as well as the secretory response 24 h later. This study shows that loratadine is an effective drug in the suppression of immediate allergic nasal symptoms. One of the beneficial effects of this drug could be a reduction in allergen-induced histamine release. A finding which further implicates that antihistamines may possess other effects than just a blocking of the H1-receptor.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1398-9995.1991.tb00618.x
