Evaluation of bone metabolism after the use of an inhaled glucocorticoid (flunisolide) in patients with moderate asthma.

OBJECTIVE

We have investigated the effects of the inhaled corticosteroid flunisolide on bone metabolism and adrenal function in patients with moderate asthma.

SUBJECTS AND DESIGN

Twenty ambulatory patients (13 females, 7 males, mean age +/- SD of 36.4 +/- 12.4 years) with moderate asthma were recruited. None had taken corticosteroids for at least 1 month. Flunisolide 500 microg was given twice a day for 10 weeks, without any other medication. Blood and urine were collected before and at the end of treatment course. Cortisol (basal and 1 h after ACTH 250 microg i.v.) was measured to evaluate adrenal function. A peak cortisol response of 496 nmol/l was considered an adequate response. Serum ionized calcium, intact PTH, plasma osteocalcin (OC) and urinary pyridinoline (Pyr) and deoxy-pyridinoline (D-Pyr) were measured to evaluate bone metabolism. Wilcoxon paired test was performed for statistical analysis. Results are expressed as mean +/- SD.

RESULTS

In most patients (85%), there was no difference after treatment with flunisolide on basal and stimulated cortisol levels. We found a significant decrease of OC (3.55 +/- 1.42 to 2.97 +/- 1.05 nmol/l) and Pyr (66.4 +/- 20.0 to 59.5 +/- 24.9 pmol/micromol creatinine) levels after treatment (P < 0.05). We also observed a positive correlation between the variations seen in pre and post treatment values of OC and Pyr/D-Pyr.

CONCLUSIONS

The use of inhaled flunisolide 1000 microg/day for 10 weeks had no suppressive effect on adrenal function in the majority of asthmatic patients studied. However, the effects seen on bone and mineral metabolism, evidenced by the significant fall in osteocalcin and pyridinoline levels, may indicate a possible systemic effect of this drug. Clinical consequences of long-term treatment with flunisolide need to be further evaluated.