Pharmacologic evaluation of loratadine (SCH 29851), chlorpheniramine and placebo

Abstract

The antihistaminic effect of loratadine (160 mg) was compared in twenty-four normal male volunteers to chlorpheniramine maleate (4 mg) and placebo in a double blinded 3-way cross-over study of latin square design. After receiving single oral doses of each medication, the wheal response to serial 0.1 ml intradermal histamine (2 µg) and saline (control) injections were recorded over a 24-h period. The calculated wheal areas were compared to baseline measurements. The results were analyzed by analysis of variance. Loratadine exhibited a more pronounced inhibition of histamine wheal formation than placebo or chlorpheniramine maleate (pn=2; chlorpheniramine,n=3; and loratadine,n=1), the relative incidence were not statistically significant.