Inhibition of immunological and non-immunological histamine release from human basophils and lung mast cells by formoterol

3-Formylamino-4-hydroxy-alpha(N-1-methyl-2-p-methoxyphenethyl-a min omethyl)benzylalcohol hemifumarate (formoterol fumarate, BD40 A, CGP 25 827 A-E) inhibited both allergic (anti-IgE) and non-allergic histamine release (calcium ionophore and human complement component C5a) from human basophils. The degree and efficacy of inhibition was comparable to that of ketotifen, equal to or better than fenoterol and ten times more potent than isoprenaline (beta 2-stimulator). Salbutamol, another beta 2-stimulator was practically ineffective in these models. Similarly the anti-IgE, calcium ionophore and complement component C5a induced release of histamine from human lung mast cells could be blocked by formoterol, its potency being again comparable to that of ketotifen. The above degranulation inhibition effect taken together with the pronounced bronchodilator property would confirm formoterol as a drug of choice in asthma with more efficient action than the other beta 2-stimulators such as fenoterol, salbutamol or isoprenaline.