Effects of isoprenaline and terbutaline on urinary excretion of histamine and its two main metabolites in systemic mastocytosis.

Both short-term and long-term effects of the beta-sympathomimetic drugs isoprenaline and terbutaline on the urinary excretion of histamine and its two main metabolites were evaluated in patients with systemic mastocytosis. In a short-term study isoprenaline and terbutaline were given intravenously during five hours to three and two patients, respectively. Compared with placebo infusion Nt-methylhistamine excretion fell during terbutaline administration, whereas during isoprenaline no changes were observed. In a long-term study three patients received a treatment with orally administered terbutaline for 24 days. In one patient a slight reduction of the excretion of the histamine metabolites was found. In another patient the excretion of histamine and its metabolites decreased especially during the eight days observation period after the end of the treatment. In this study we saw occasionally large and rapid changes occurring simultaneously in all three urinary parameters of histamine release. In conclusion, terbutaline can reduce histamine release in systemic mastocytosis. However, because of the small symptomatic and biochemical effects found in our patients, the clinical significance of beta-sympathomimetic drug treatment in this disease has yet to be established.