University of Michigan
Department of Pediatrics
Evidence-Based Pediatrics Web Site

Question

• In adult patients with seasonal allergic rhinitis, can leukotriene inhibitors (LTs) provide a superior effect to selective anti-histamine agents (H1 blockers) for the relief of allergy symptoms?

Clinical Bottom Lines

1. No evidence exists showing a superior effect of LTs over H1 blockers for the relief of daytime allergy symptoms.
2. No evidence exists showing an equivalent effect of LTs over H1 blockers for the relief of daytime allergy symptoms, though the data appears promising.
3. Mild evidence exists to support the additive effect of LTs and H1 blockers for the relief of daytime allergy symptoms.

Summary of Key Evidence

1. Concomitant use of Singulair and Claritin significantly (p<.001) improved daytime allergic symptom scores compared with placebo (NNT = 3).
2. Concomitant use of Singulair and Claritin did not significantly improve daytime allergic symptom scores compared with each agent separately.

Additional Comments

• Nasal challenge studies have shown that both histamine and cysteinyl leukotrienes activate inflammation in allergic states, providing sound biochemical reasoning for the use of LTs in allergic rhinitis.
• Further evidence, namely a dedicated equivalency study, needs be gathered in order to replace H1 blockers with LTs as single-agent therapy for allergic rhinitis.
  
• Though uncommon, a worrisome side effect profile may make LTs unfeasible for the treatment of allergic rhinitis, especially in children.

Citation

1. Meltzer E, Malmstrom K. Concomitant montelukast and loratadine as treatment for seasonal allergic rhinitis. J Allergy Clin Immunol 2000; 105:917-22.
   
2. Pullerits T, Praks L. Randomized placebo-controlled study comparing a leukotriene antagonist and a nasal glucocorticoid in seasonal allergic rhinitis. Am J Respir Crit Care Med 1999; 159:1814-18.
   
3. Meltzer E. Clinical evidence for antileukotriene therapy in the management of allergic rhinitis. Ann Allergy Asthma Immunol 2002; 88: 23-9.
   
4. Krysan DJ, Kemper AL. Claims of equivalence in RCTs of the treatment of bacterial meningitis in children. Pediatric Infectious Disease Journal 2002; 21:753-8.

CAT Author: Paul Trani, MD

CAT Appraisers: Alex Kemper, MD

Date appraised: February 10, 2003