Skin bruising, adrenal function and markers of bone metabolism in asthmatics using inhaled beclomethasone and fluticasone

Pharmacokinetic/pharmacodynamic modelling of effects of dexamethasone and prednisolone in combination with endogenous cortisol on lymphocyte counts and systemic markers of bone turn over and inflammation in healthy and asthmatic men

OBJECTIVE

To compare potency and efficacy of dexamethasone (DEXA) and prednisolone (PRED) in assumed equipotent doses in combination with endogenous cortisol, using lymphocyte counts, plasma osteocalcin (OC), and eosinophilic cationic protein (ECP) as effect variables and to evaluate potential differences between healthy subjects and asthmatic patients.

METHODS

Eight healthy subjects and six asthmatic patients who had stopped taking their regular inhaled glucocorticosteroid treatment (ICS) for 1 week, were given an IV bolus of DEXA and PRED in assumed equipotent doses of 2.0 mg and 12.5 mg, respectively, on separate occasions, in combination with subcutaneously injected granulocyte-colony-stimulating factor (G-CSF) as a stimulant for ECP production. Plasma levels of DEXA, PRED, cortisol and effect variables were determined over 25 h and pharmacokinetic-pharmacodynamic (PK-PD) modelling was performed.

RESULTS

Baseline cortisol concentration was lower in patients than in healthy subjects. Both of the exogenous glucocorticoids (GCs) diminished cortisol production. In the healthy subjects, the cortisol production remained suppressed for the full duration of the study day after DEXA but not after PRED. In the asthmatic patients though, the reappearance of the endogenous production of cortisol was seen after both DEXA and PRED. The E(max) values for lymphocyte counts and OC showed that cortisol acted as partial, and DEXA and PRED as full agonists. The observed responses of DEXA and PRED suppressing cortisol, OC and lymphocyte counts were all of the same relative order of magnitude, in accordance with the estimated PD parameters. However, cortisol was estimated to have very little effect on ECP and modelling further predicted that DEXA and PRED were only partial agonists for this effect, without a difference between healthy and asthmatic subjects. Yet, in healthy subjects, the area under the concentration-time curves (AUCs) indicated unexpectedly that ECP was only suppressed after PRED and not after DEXA, while in patients it was suppressed after both GCs. The rank order of potency on lymphocyte counts, OC and ECP was DEXA>PRED>cortisol, although the different relative potencies of the three GCs involved were not the same for all of the three effect variables and differences were also found between healthy and asthmatic subjects.

CONCLUSION

PK-PD modelling studies of GCs demonstrated not only differences in potency of DEXA and PRED on the measured systemic markers, but also different potencies per target tissue and differences between healthy and asthmatic men. The effects caused by the achieved blood concentrations of DEXA and PRED, expressed as AUCs of the effect variables, were in accordance with their respective E(max) values in case of the lymphocytes and OC but not for ECP.

Bone mineral density in subjects with mild asthma randomised to treatment with inhaled corticosteroids or non-corticosteroid treatment for two years

BACKGROUND

Inhaled corticosteroids are clearly beneficial for patients with asthma of moderate severity, but the risks and benefits of using them in patients with milder asthma are less clear. We have compared the change in bone mineral density over 2 years in adults with mild asthma randomised to receive an inhaled corticosteroid or non-corticosteroid treatment.

METHODS

Subjects with mild asthma (mean forced expiratory volume in one second (FEV(1)) 86% predicted, mean age 35 years, taking beta agonists only) were randomised to receive inhaled budesonide, inhaled beclomethasone dipropionate, or non-corticosteroid treatment for 2 years in a prospective randomised open study in 19 centres in France, New Zealand, Spain, and the UK. The corticosteroid dose was adjusted according to a written self-management plan. The main outcome measure-change in bone mineral density after 6, 12, and 24 months-was measured "blind". Secondary outcomes included lung function, the relation between change in bone density and inhaled steroid dose and change in biochemical markers of bone metabolism.

RESULTS

Of 374 subjects randomised, 239 (64%) completed the study and were included in the analysis. The median daily doses of inhaled budesonide (n=87) and beclomethasone (n=74) were 389 microg and 499 microg, respectively. Subjects treated with an inhaled corticosteroid had better asthma control than those in the reference group (n=78). Change in bone mineral density did not differ between the three groups over the 2 years, nor did it correlate with changes in markers of bone metabolism. The mean change in bone mineral density over 2 years in the budesonide, beclomethasone dipropionate, and reference groups was 0.1%, -0.4%, and 0.4% for the lumbar spine and -0.9%, -0.9%, and -0.4% for neck of the femur. Mean daily dose of inhaled steroid was related to reduction in bone mineral density at the lumbar spine but not at the femoral neck.

CONCLUSION

In subjects with mild asthma an inhaled corticosteroid provided better asthma control than alternative non-corticosteroid treatment with no difference in change in bone mineral density over 2 years. The relation between dose of inhaled corticosteroid and change in bone density at the lumbar spine may be due to a direct effect of inhaled corticosteroids on bone. Since inhaled steroid dose is also related inversely to lung function, an effect of asthma severity on bone density was also possible.