Preventive effect of ketotifen, a new antiallergic agent, on histamine-induced bronchoconstriction in asthmatics.
The preventive effect of ketotifen, a new drug with anti-histaminic and antiallergic properties, on histamine-induced bronchoconstriction was studied by open assessment in twenty-four adult patients with extrinsic asthma. A single oral dose of 1 mg ketotifen reduced the post-histamine mean drop in peak expiratory flow from 33 to 16% of the basal values (P less than 0.001). After a 4 weeks' regimen of 1 mg ketotifen twice daily the post-drug histamine-induced fall in PEF was further significantly reduced (P less than 0.001). Tests performed after 8 and 12 weeks of treatment showed no additional decrease in bronchial reactivity to histamine. Tests performed 1 week after cessation of treatment showed return of bronchial reactivity to the pretreatment level. The results suggest that a single dose of ketotifen has a marked preventive effect on histamine-induced bronchoconstriction and that this effect is enhanced during continued treatment.
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000517:prevention & control*; D003251:Constriction, Pathologic / Q000209:etiology*; D005260:Female; D005541:Forced Expiratory Volume; D006632:Histamine / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate; D010880:Piperidines / Q000009:adverse effects / Q000627:therapeutic use*; D013876:Thiophenes / Q000009:adverse effects / Q000627:therapeutic use*; D014797:Vital Capacity
D006634:Histamine H1 Antagonists; D010880:Piperidines; D013876:Thiophenes; D006632:Histamine