A comparison of the in vivo effects of ketotifen, clemastine, chlorpheniramine and sodium cromoglycate on histamine and allergen induced weals in human skin.

The effect of ketotifen was compared with that of clemastine and chlorpheniramine, known antihistamines, and sodium cromoglycate, a drug considered to have mast cell "stabilizing' properties on histamine and allergen wealing reactions in human skin, in random order, double-blind, placebo controlled studies. Ketotifen was significantly more potent in the inhibition of both histamine (P less than 0.001) and allergen (P less than 0.001) skin wealing reactions than either clemastine or chlorpheniramine. Sodium cromoglycate had no significant effect on either histamine or allergen skin wealing reactions in any of the concentrations tested. However ketotifen, like clemastine, had a significantly greater inhibitory effect on histamine than on allergen induced weals (P less than 0.001) and both drugs were shown to act as competitive antagonists of histamine. Ketotifen has been shown to be a potent anti-histamine but there is no evidence from these in vivo studies to suggest that it has any additional inhibitory activity on release of mediators from mast cells in human skin.

RCT Entities:   Population Interventions Outcomes