Ketotifen does not inhibit asthmatic reactions induced by toluene di‐isocyanate in sensitized subjects

Abstract
Summary: In order to determine whether treatment with ketotifen inhibits asthmatic reactions induced by toluene di‐isocyanate (TDI), we studied six sensitized subjects with previously demonstrated dual or late asthmatic reaction after inhalation challenge with TDI. Ketotifen (1 mg b.i.d., orally) or placebo was administered for 7 days to the examined subjects, according to a double‐blind, cross‐over, placebo‐controlled study design. When the subjects were treated with either ketotifen or placebo, FEV1 markedly decreased after exposure to TDI. These results suggest that the anti‐asthmatic agent ketotifen is not effective in TDI‐induced asthma and suggest that it should not be used in the prophylaxis of asthmatic reactions induced by TDI in sensitized subjects.