Loratadine is a new selective peripheral
histamine H1-receptor antagonist, that is orally effective, long-acting, and devoid of significant central and autonomic nervous system activity. Its safety and efficacy were evaluated in a 28-day study conducted in patients with
chronic idiopathic urticaria. Patients were randomly assigned to one of three treatment groups (
loratadine, 10 mg OD;
terfenadine, 60 mg BID; or placebo). Evaluation of efficacy included weekly assessments of the individual disease signs and symptoms, the overall disease condition, and therapeutic response to treatment. Throughout the 28-day treatment period progressive improvement was observed in the
loratadine and
terfenadine treatment groups; however, at each evaluation,
loratadine was significantly more effective than placebo (P less than .01) and clinically more effective than
terfenadine in reducing disease signs and symptoms.
Terfenadine was significantly more effective than placebo at day 7 and endpoint (last valid visit). The overall therapeutic response at the endpoint of treatment was rated as marked or complete relief of symptoms in 64%, 52%, and 25% of the patients in the
loratadine,
terfenadine, and placebo treatment groups, respectively.
Loratadine was well tolerated and comparable to
terfenadine and placebo in incidence of adverse experiences. Sedation was reported in one patient each in the
terfenadine and placebo treatment groups and an
anticholinergic side effect (dry mouth) in one
terfenadine-treated patient. No
sedative or
anticholinergic side effects were observed in patients receiving
loratadine. We concluded that
loratadine, 10 mg, once daily is a safe and effective treatment for symptomatic relief of
chronic idiopathic urticaria.