The efficacy of histamine antagonists as antipruritics in experimentally induced pruritus.

1. The antipruritic ability of histamine (H1 and H2) antagonists alone and in combination in experimentally induced pruritus has been investigated in 12 normal human volunteers. 2. A combination of cimetidine (H2 anatagonist) and chlorpheniramine (H1 antagonist) proved effective in suppressing itch that was artificially induced by the application of papain and histamine. 3. The combination was more effective than chlorpheniramine or cimetidine alone or placebo. 4. The results suggest that both H1 and H2 receptors are involved in the mediation of pruritus.