Background: The anti-inflammatory effects of chronic dosing with mediator antagonists as add-on therapy to inhaled corticosteroids (ICS) in asthma remain to be fully established. We studied the effects of fexofenadine (FEX) and montelukast (ML) at clinically recommended doses using adenosine monophosphate (AMP) bronchial challenge as the primary outcome.
Methods: 18 atopic asthmatics with mean ICS dose of 631µg, were randomised in double-blind, cross-over fashion to receive for 1 week either FEX 180mg, ML 10mg or placebo (PL), following a 1-week washout period. AMP PC20 was measured after each washout and randomised treatment period.
Results: AMP PC20 (mg/ml) values after washout were similar: 74 vs. 73 vs. 71 for FEX, ML and PL respectively. There were significant improvements (p < 0.05) in AMP PC20 vs. PL (78); with FEX (127), and ML (121). Spontaneous recovery after AMP challenge as area under the 60-minute time-response curve (%.min) was enhanced with ML (352) vs. FEX (758), and vs. PL (683). Both FEX and ML suppressed levels of exhaled nitric oxide while only ML reduced the peripheral blood eosinophil count vs. PL. Morning and evening peak expiratory flow were higher and salbutamol rescue were reduced with FEX and ML, vs. PL.
Conclusion: Chronic dosing with FEX and ML as add-on therapy improved AMP PC20 and other surrogate inflammatory markers along with asthma diary outcomes in ICS treated atopic asthmatics. Further studies are indicated to evaluate long-term add-on effects of FEX on asthma exacerbations.