We evaluated the comparative effectiveness of usual clinically recommended doses of desloratadine (DES), fexofenadine (FEX) and levocetirizine (LEV), on nasal adenosine monophosphate (AMP) challenge in patients with perennial allergic rhinitis (PAR).

16 patients with PAR were randomized in double-blind cross-over fashion to receive single doses of DES 5mg, FEX 180mg, LEV 5mg, or placebo (PL), with nasal AMP challenge performed 12 hours after dosing. Measurements of peak nasal inspiratory flow (PNIF) were made over 60 minutes after nasal AMP challenge.

Pre-challenge values (mean ± SEM) for PNIF (l/min) were not significantly different comparing all groups; DES (129 ± 9), FEX (128 ± 11), LEV (128 ± 13), and PL (128 ± 12). The maximum % PNIF fall from baseline over 60 minutes after nasal AMP challenge was significantly attenuated (p<0.05) compared to PL (50 ± 4), with DES (32 ± 5), FEX (36 ± 4), and LEV (36 ± 4). The area under the 60-minute time-response curve (AUC %.min) was also significantly attenuated (p<0.05) compared to PL (2110 ± 268), with DES (1126 ± 285), FEX (1225 ± 255), and LEV (1261 ± 194). There were no significant differences when comparing values for either the maximum % PNIF fall or AUC after nasal AMP challenge between the three H₁-antihistamines.

DES, FEX and LEV were equally effective in attenuating the response to nasal AMP challenge. However, further long-term studies will be required to study their comparative effects on nasal symptoms, quality of life, as well as on nasal inflammatory cells.