Drug Therapy than histamine. Now there is a good evidence for the production of leukotrienes both in models of asthma and in clinical asthma. Allergen challenge studies of atopic asthmatic patients found that, there is an increase in leukotriene levels in bronchoalveolar lavage fluid and a rise in urinary levels of LTE4, greatest during the early asthmatic response. Recently in asthmatic patients, leukotrienes have been found in lavage fluid and in acute severe asthma leukotriene levels in the blood have been reported to be increased.3 The potent LTRAs can block upto 70-80% of early responses to inhaled allergen and nearly 50% of the late asthmatic responses. Drugs which antagonize leukotriene receptors or inhibit leukotriene synthesis have now been shown to be effective in clinical models of asthma for antigen- and exercise-induced bronchoconstriction, and in clinical trials they have improved the control of asthma. Nearly 2-5% of adult asthmatic patients are found to be sensitive to aspirin. In these patients, leukotriene antagonists improve basal airway function and can block the effects of aspirin. So, leukotriene antagonists can also be beneficial in this group of patients, whose asthma is difficult to treat.3 Among the latest LTRAs, montelukast is now widely used in clinical otolaryngology practice.3 Montelukast was approved by the FDA in 1998. The safety and effectiveness of montelukast has been demonstrated in children as young as six months of age. Role of Leukotriene Receptor Antagonists in AR LTRAs are found to be as effective as antihistamines in AR patients and they are noted to be very effective, when used as they can improve symptoms and qualityof-life in patients with seasonal AR. A study compared the clinical efficacy of LTRAs with antihistamines, nasal corticosteroids in patients with AR and nasal polyposis. This study showed that LTRAs reduced mean daily rhinitis symptom scores 5% (95% confidence interval [CI]: 3-7%) more than the placebo.4 Another multicenter, double-blind trial in patients with spring seasonal AR, randomly assigned to oncedaily montelukast (10 mg), loratadine (10 mg) or placebo demonstrated that both the day-time and night-time nasal symptom scores were significantly (p < 0.001) reduced with montelukast and loratadine 14
compared with placebo.5 The quality-of-life was also improved with montelukast and loratadine versus placebo (p < 0.005). In an another study, after two weeks of treatment, peripheral blood eosinophil counts were found to be significantly (p â&#x2030;¤ 0.001) decreased with montelukast but not with loratadine or placebo.6 The effects of an LTRA and antihistamine oral combination (montelukast plus cetirizine) were compared with mometasone, an intranasal steroid. The study showed that the combination of montelukast plus cetirizine produced significant (p < 0.05) improvements compared with placebo in the indices like peak nasal expiratory flow rate, nasal oral index, nasal symptoms, nasal itching, nasal blockage and daily activity score.7 This study found that there were no significant differences between mometasone and montelukast plus cetirizine. Efficacy of Montelukast in AR and Asthma Montelukast 10 mg is a safe and effective treatment for patients of both asthma and AR. Many studies have confirmed the effectiveness of montelukast 10 mg orally in adults with both asthma and AR. A phase IV study was done to investigate the efficacy and safety of montelukast 10 mg in adults with both asthma and AR in a real-life setting.8 This study found that after treatment with 10 mg montelukast, 86.5% of patients reported a strong or marked improvement in day-time asthma symptoms and 88.5% reported improvement in night-time symptoms and a high proportion of patients had a strong or marked improvement in all symptoms of AR [i.e., sneezing/itching (84%), rhinorrhea (81.7%), nasal congestion (79.3%)]. The study also found that the use of asthma and rhinitis medication was also reduced and 92.3% patients intended to continue montelukast therapy. This study concluded that montelukast is well-tolerated for both AR and asthma patients. Banasiak NC et al also reported that leukotriene modifiers are a useful alternative medication for use in children with mild persistent asthma, especially those who are unable to comply with inhaled steroids.9 They are also considered to be an additional medication for the step-up approach, or combination therapy, for moderate and severe persistent asthma not controlled with ICS alone. Asian Journal of Paediatric Practice, Vol. 14, No. 3