Furosemide inhibits in vitro histamine release induced by antigens and anti-IgE.

We used 56 samples of heparinized blood of patients with asthma and/or allergic rhinitis, which were stimulated with Dermatophagoides pteronyssinus or gramineous pollen and anti-IgE in order to study the effect of furosemide on histamine release in basophils. At the same time, blood samples incubated in furosemide in different concentrations (2.5 microM to 1.49 mM) were also subjected to the same stimuli. Results showed a linear and dose-dependent inhibition of histamine release for antigens (r = 0.96; p < 0.01) and anti-IgE (r = 0.95; p < 0.05), reaching 95% at maximum inhibition. These results support the hypothesis that furosemide may act on mastocytes and basophils, thus inhibiting the release of histamine and other mediators.