Leukotriene receptor antagonists in the treatment of allergic rhinitis

Leukotriene receptor antagonists (LTRAs) have been long used in the therapy of some forms of asthma. Indeed, cysteinyl-leukotrienes (cysteinyl-LTs), potent lipid mediators derived from the oxidative metabolism of the arachidonic acid, are synthesized in response to different immune and inflammatory stimuli, and are deeply involved in the pathophysiology of asthma. A number of molecular and clinical studies substantiate a role for cysteinyl-LTs and their receptors also in allergic rhinitis, indicating that they contribute to nasal allergy increasing blood flow and nasal airway resistance, nasal mucous secretion and congestion. Considering that cysteynil-LTs play a critical role in the pathogenesis of both these diseases, a common therapeutic approach would seem logical. The LTRA therapeutic potential in allergic rhinitis has been, therefore, evaluated in a number of clinical trials that have demonstrated their safety and efficacy. LTRAs, thus, can provide an effective treatment option for patients with allergic rhinitis, and are generally used as an adjunct in the treatment of a patient who does not have an adequate response to antihistamines, a nasal corticosteroid, or both. In addition, LTRAs are beneficial for large proportion of patients suffering also from asthma. However, despite encouraging results, their place in the therapy of allergic rhinitis is not completely defined, and, as today, topical nasal steroid still should be considered the first-line therapy. It is likely that future developments in the pharmacogenetic will allow a more effective use of these drugs as, at present it is largely recognized that different genetic phenotypes reflect different responses to LTRAs. Today, unfortunately, it is not yet possible to identify patients with an LT-“dependent” disease and to predict responders or non-responders other than by use of a trial of therapy