“…Analo gously to the findings in animals, it was also found that ipratropium bromide has a favorable effect against bronchospasm elicit ed in humans by acetylcholine inhalations [26,33], However, it had little or no effect with histamine or serotonin inhalation. Also, prior administration of ipratropium bromide was not completely effective in reducing the increase of airway resistance evoked by allergen challenge [4,7,14,18,19,26,27,34,35].…”