DIFFERENTIAL-EFFECTS OF NEW-GENERATION H-1-RECEPTOR ANTAGONISTS IN PRURITIC DERMATOSES

In search of an improved treatment of pruritic dermatoses, we have stu died azelastine, a novel H-1-receptor antagonist, during a 2-week trea tment period, using a double-blind, placebo-controlled design. The pot ent H-1-antagonist cetirizine was used for comparison. Symptoms were r ecorded daily by the patients on a diary card, using a 4-point scale. The same parameters and adverse events were evaluated at weekly interv als, and global improvement was evaluated at the end of treatment. In all 230 evaluable patients with moderate to severe itching, azelastine caused an overall significant improvement in comparison to placebo (P =0.02), with significance also for pruritus (P=0.01 after 1 week and P =0.02 after 2 weeks). Both drugs reduced itching more effectively in u rticaria than in atopic eczema. Azelastine was superior to cetirizine in reducing pruritus, whereas cetirizine caused a more marked reductio n of whealing. Both drugs rarely caused fatigue and dry mouth, but tas te perversion occurred only in azelastine treated patients (9.7%) and headaches only with cetirizine (10.4%). Therefore, the two H-1-blocker s exert differential effects on pruritus verses whealing and a distinc tive adverse events pattern. The data also underline the low efficacy of antihistamines in atopic eczema, compared to urticaria.