Effect of H1-receptor blockade on anthralin inflammation

The effect of terfenadine, an H1-receptor antagonist, on anthralin inflammation was studied in 12 subjects. Subjects were randomised to receive terfenadine 60 mg or placebo b.d. in a double-blind, cross-over study. Anthralin 5, 10 and 20 micrograms in 10 microliters chloroform was pipetted onto flexor forearm skin. Anthralin inflammatory oedema and erythema were measured using Harpenden calipers and a reflectance photometer, 48 h after anthralin application. After a 3-day washout period, placebo and terfenadine were restarted and the procedures repeated on the opposite arm. Anthralin erythema and oedema increased with dose but the dose-response curves showed no significant difference with or without terfenadine (p greater than 0.05). This study shows that H1-receptor blockade does not inhibit anthralin inflammation.