ABSTRACT
Montelukast is a potent, oral, specific leukotriene D 4 receptor antagonist recently approved for the treatment of chronic asthma in patients aged 6 years and older. Loratadine is a long acting selective HI - receptor antagonist devoid of significant sedative or anticholinergic properties. In addition to its activity as an HI - receptor antagonist, loratadine has demonstrated other anti-allergic properties. In this work, the in-vitro experiments were performed to compare the effectiveness of combination of montelukast [1.6 x 10 [-6] M/L] and loratadine [1.6 x 10 [-6]6 M/L] on antigen-induced contractions in sensitized isolated guinea pig tracheal spirals. They revealed that pretreatment with montelukast and loratadine either combined or each alone produced a significant reduction in the ovalbumin-induced contractionsin the doses 0.1, 1, 10 and 100 mg/ml. The EC5O values of ovalbumin-induced contractions were 27, 139.19 and 3.34 X 10 [12] ug/ ml after pretreatment with morclukast. loratadine and their combination, respectively. It has been found that montelukast-loratadine combination was more effective than montelukast alone. Results of the clinical study demonstrated that Montelukast alone and Montelukast-loratadine administered once daily at bedtime to asthmatic patients of mild to moderate asthma and are sub-optimally controlled with glucocorticoids and theophylline showed significant improvements in objective and subjective measurements of asthma control. Montelukast-loratadine demonstrated significant improvements over Montelukast alone in FEV 1 [primary end point], PEFR, daily B2 agonist use, daytime symptom scores [secondary end points] and nocturnal asthma symptoms score. In conclusion, montelukast-loratadine combination provides additional benefit compared with montelukast alone in mild to moderate asthma. In addition, montelukast provides a replacement therapy for glucocorticoids and theophylline in these patients