Effect of inhaled triamcinolone on bronchial hyperreactivity and airways obstruction in asthma

We measured changes in methacholine bronchial hyperreactivity and airways obstruction in 37 asthmatics treated with inhaled triamcinolone for 6 weeks. All received regular bronchodilator therapy but not steroids or cromolyn. Initial studies included spirometry and the provocative concentration of methacholine required to decrease the FEV1 by 20% (PC20). Patients were randomized into two groups: those given inhaled triamcinolone, 200 micrograms four times daily (T) by metered dose inhaler, and those given a placebo inhaler (P). Daily AM and PM peak flow measurements were recorded, while PC20 and pulmonary function tests were obtained at 3 and 6 weeks. Change in canister weight was used to determine treatment compliance. The PC20 of T increased from a baseline 1.00 mg/mL to 2.90 mg/mL at 6 weeks, whereas in P it decreased from 1.15 mg/mL to 1.05 mg/mL. Percent change in PC20 (delta PC20) for each patient was defined as: [(PC20(week 6)--PC20(baseline]/PC20 (baseline)] X 100. At 6 weeks, this was 290% in T versus 65% in P (P less than .05). Likewise, at 6 weeks T was significantly greater than P with respect to: delta FEV1 (4.1% versus -3.8%, P less than .05) and delta FEF25-75% (20.3% versus -5.6%, P less than .01). Patients were further separated into higher and lower complier subgroups. In T, higher compliers showed more improvement at 6 weeks than lower compliers in: delta PC20 (533.3 versus 67.8%, P less than .05), delta FEV1 (8.7 versus -1.7%, P less than .01), and delta FEF25-75% (31.9 versus 1.1%, P less than .01). These data suggest that triamcinolone improves bronchial hyperreactivity as well as airways obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)