PLASMA TERBUTALINE LEVELS IN NEBULIZATION TREATMENT OF ACUTE ASTHMA

A study was made of the effects of inhaling 5 mg of terbutaline and 0.5 mg of ipratropium bromide in 11 patients arriving at our emergency room with acute asthma (FEV1 less-than-or-equal-to 50% of the predicted). Measurable plasma levels of terbutaline before treatment were found in all patients who reported having taken oral terbutaline (mean value 30 nmol/l, range 11-89). A significant correlation was found between the reported terbutaline medication and the measured terbutaline plasma concentration (p < 0.01). Plasma terbutaline had increased by 6-20 (mean 15) nmol/l 60 min after the start of treatment and by 6-45 (mean 14) nmol/l at 120 min, compared with the pre-treatment value. A highly significant decrease in dyspnoea and an increase in PEF and FEV1 was measured (p < 0.01) after treatment, while no significant changes in respiratory rate, pulse rate, blood pressure or tremor were recorded. A significant positive correlation was found between DELTA-plasma terbutaline and DELTA-systolic blood pressure 120 min after treatment (p < 0.05), but apart from this no statistically significant correlations were found between plasma terbutaline on arrival or DELTA-plasma terbutaline and the other measurements of the effect of treatment. One of the advantages of adding ipratropium to nebulised beta-agonist treatment might be that it permits the use of lower doses of beta-2-agonist and thereby reduces the systemic side-effects of the treatment.