Comparison of azelastine and chlorpheniramine in the treatment of mastocytosis.

BACKGROUND

Azelastine, a novel antiallergic medication, was compared with chlorpheniramine maleate for efficacy and safety in the treatment of systemic mastocytosis.

METHODS

Fifteen subjects with mastocytosis participated in a double-blind, randomized, three-period, crossover trial, which compared an azelastine regimen of 4 mg or 8 mg every 12 hours with a chlorpheniramine regimen of 12 mg every 12 hours. Response to therapy was assessed by daily symptom scores, extinction dilution skin tests, plasma histamine levels, and global evaluations.

RESULTS

Subjects' mean wheal area responses provoked by histamine or morphine sulfate were significantly lowered by azelastine when compared with chlorpheniramine. Plasma histamine levels in subjects receiving azelastine or chlorpheniramine were not significantly different. There were no significant differences between azelastine and chlorpheniramine in individual symptom scores or global evaluations except that azelastine at both doses significantly relieved pruritus and at 4 mg significantly relieved abdominal pain and that chlorpheniramine was associated with less fatigue in comparison to azelastine at 8 mg.

CONCLUSIONS

It thus appears that azelastine is superior to chlorpheniramine in suppressing skin responses to histamine and morphine sulfate and in suppressing pruritus in patients with mastocytosis. However, when all parameters are considered, neither drug is clearly superior for the treatment of patients with mastocytosis.