We evaluated the effects of usual clinically recommended doses of fexofenadine (FEX), montelukast (ML), and FEX+ML combination, compared to placebo (PL), on nasal adenosine monophosphate (AMP) challenge in patients with perennial allergic rhinitis (PAR).

12 PAR patients were randomized in a double-blind, crossover fashion to receive for 1 week, either FEX 180 mg, ML 10 mg, FEX 180 mg + ML 10 mg combination, or PL, with nasal AMP challenge performed 12 hours after dosing. The primary outcome was measurement of peak nasal inspiratory flow (PNIF) made over a 60-minute period after nasal challenge with a single 400 mg/ml dose of AMP. Domiciliary total nasal symptoms were measured as a secondary outcome.

There was significant attenuation (p<0.05) of the mean maximum % PNIF fall from baseline after nasal AMP challenge vs. PL: 48, with FEX: 37; 95%CI for difference (2–20), ML: 35 (4–22), and FEX+ML: 32 (7–24). The area under the 60-minute time-response curve (AUC %.min) was also significantly attenuated (p<0.05) vs. PL: 1893, with FEX: 1306 (30–1143), ML: 1246 (214–1078), and FEX+ML: 1153 (251–1227). There were no significant differences for FEX vs. ML vs. FEX+ML comparing either the maximum or AUC responses. The total nasal symptom score (out of 12) was also significantly improved (p<0.05) vs. PL: 3.3, with FEX: 2.1 (0.3–2.0), ML: 2.0 (0.5–1.9), and FEX+ML: 2.5 (0.1–1.4).

FEX and ML as monotherapy significantly attenuated the response to nasal AMP challenge and improved nasal symptoms compared to PL, while combination therapy conferred no additional benefit.