Adrenal suppression with inhaled corticosteroids

Pharmacokinetic and pharmacodynamic comparison of hydrofluoroalkane and chlorofluorocarbon formulations of budesonide

AIMS

A hydrofluoroalkane formulation of budesonide pressurized metered-dose inhaler has been developed to replace the existing chlorofluorocarbon one. The aim of this study was to evaluate the pharmacokinetic and pharmacodynamic characteristics of both formulations.

METHODS

Systemic bioavailability and bioactivity of both hydrofluoroalkane and chlorofluorocarbon pressurized metered-dose inhaler formulations at 800 µg twice daily was determined during a randomized crossover systemic pharmacokinetic/pharmacodynamic study at steady state in healthy volunteers. Measurements included the following: plasma cortisol AUC(24h) [area under the concentration-time curve (0-24 h)], budesonide AUC(0-12h) and C(max) . Clinical efficacy was determined during a randomized crossover pharmacodynamic study in asthmatic patients receiving 200 µg followed by 800 µg budesonide via chlorofluorocarbon or hydrofluoroalkane pressurized metered-dose inhaler each for 4 weeks. Methacholine PC(20) (primary outcome), exhaled nitric oxide, spirometry, peak expiratory flow and symptoms were evaluated.

RESULTS

In the pharmacokinetic study, there were no differences in cortisol, AUC(0-12h) [area under the concentration-time curve (0-12 h)], T(max) (time to maximum concentration) or C(max) (peak serum concentration) between the hydrofluoroalkane and chlorofluorocarbon pressurized metered-dose inhaler. The ratio of budesonide hydrofluoroalkane vs. chlorofluorocarbon pressurized metered-dose inhaler for cortisol AUC(24h) was 1.02 (95% confidence interval 0.93-1.11) and budesonide AUC(0-12h) was 1.03 (90% confidence interval 0.9-1.18). In the asthma pharmacodynamic study, there was a significant dose response (P < 0.0001) for methacholine PC(20) (provocative concentration of methacholine needed to produce a 20% fall in FEV(1) ) with a relative potency ratio of 1.10 (95% confidence interval 0.49-2.66), and no difference at either dose. No significant differences between formulations were seen with the secondary outcome variables.

CONCLUSIONS

Hydrofluoroalkane and chlorofluorocarbon formulations of budesonide were therapeutically equivalent in terms of relative lung bioavailability, airway efficacy and systemic effects.

Hypothalamic-pituitary-adrenal axis suppression in asthmatic children on inhaled and nasal corticosteroids--more common than expected?

BACKGROUND

Hypothalamic pituitary adrenal axis suppression (HPAS) when treating asthmatic children with inhaled corticosteroids (ICS) is thought to be rare.

OBJECTIVE

To determine the prevalence of HPAS in asthmatic children treated with ICS and nasal steroids (NS).

METHODS

Twenty-six asthmatic children were recruited. Clinical features of HPAS, height, weight, height and weight velocity, steroid dose, adherence, symptom control and lung functions were documented. Metyrapone test was performed if the serum cortisol was > 83 nmol/L (> 3 microg/dL).

RESULTS

No child had a serum cortisol < 83 nmol/L (< 3 microg/dL). Prevalence of HPAS was 35 (CI = 17%-56%). Daily NS dose/ m2 and cumulative NS dose/m2 were significantly (p = 0.03) inversely correlated with the post-metyrapone ACTH (r = -0.42 for both). Current ICS dose was not associated with the post-metyrapone ACTH (r = 0). There was a weak correlation with the daily ICS dose/m2 (r = -0.12) and cumulative ICS dose/m2 (r = -0.26).

CONCLUSIONS

A third of asthmatic children on ICS and NS develop HPAS. Contributing factors are the use of NS, body size and cumulative dose of ICS.

Supervised step-down of inhaled corticosteroids in the community--an observational study

INTRODUCTION

Current asthma guidelines recommend step-down of inhaled corticosteroids (ICS) to the minimum dose required for control of symptoms.

AIM

To determine if supervised step-down of (ICS) in the community has any effect on asthmatic inflammation.

METHODS

119 Community based asthmatics underwent progressive step-down of therapy until they became unstable or reached an (ICS) dose of ≤200 μg beclomethasone dipropionate (BDP) or equivalent. Once unstable, participants stepped back up to the last stable dose of ICS. Exhaled nitric oxide (NO) and mannitol challenge were performed at the start and end of step-down. Asthma Quality of Life Questionnaire (AQLQ) and spirometry were recorded at each step-down visit.

RESULTS

The median (interquartile range) BDP equivalent dose was significantly higher pre vs. post step-down: 400 μg (400-800) and 250 μg (200-400) per day respectively (P < 0.05). Examination of change in PD(10) in individual patients revealed that 34% had an improvement (>+1 dd), 47% had no change (±-1 dd), and 19% had a worsening (<-1 dd). The geometric mean fold ratio in NO for pre vs. post was 0.96 (95% CI 0.87 to 1.06, P = 0.43). Mean (SEM) values for FEV(1) were 86.2% (1.51) vs. 84.5% (1.46) (P = 0.04). There was a significant improvement in AQLQ.

CONCLUSIONS

We have demonstrated that a significant reduction in ICS dose may be achieved in a community setting without any worsening of airways inflammation or lung function, and with an associated improvement quality of life in the majority of patients. This apparent disconnect may reflect enhanced adherence due to supervision of step-down.

Systemic bioavailability of hydrofluoroalkane (HFA) formulations of fluticasone/salmeterol in healthy volunteers via pMDI alone and spacer

AIM

To compare a test version of HFA fluticasone/salmeterol (FP/SM) combination inhaler (Neolab, UK) with the reference product Seretide (GlaxoSmithKline, UK).

METHODS

An in vitro Anderson cascade impactor was used to compare the fine particle dose (<4.7 microm). Two separate randomized cross-over studies were performed to compare the systemic bioavailability of test vs. reference (T vs. R) formulations of FP/SM 250/25 microg pMDI in healthy volunteers. In study 1 blood pharmacokinetic analysis using oral charcoal block was performed over 24 h following a single dose of four puffs via pMDI alone. In study 2 systemic bioactivity was measured following single doses of four and eight puffs via a spacer device: serum potassium (K(+)) to reflect SM, and overnight urinary cortisol : creatinine (OUCC) for FP. An early pharmacokinetic profile was also assessed over 120 min.

RESULTS

The in vitro fine particle dose was similar for test vs. reference pMDI alone and via spacer. The results of both studies were consistent: No significant differences between formulations were seen in terms of FP kinetics. Analysis of SM kinetics revealed superiority of the test product. No significant dose-response or difference in T : R ratio was noted for OUCC. Fall in K(+) revealed a significant dose-response with a non-significant T : R ratio.

CONCLUSIONS

The in vitro fine particle dose may not predict pharmacokinetic and systemic pharmacodynamic outcomes. Single dosing studies with fluticasone/salmeterol 250/25 microg via pMDI or with spacer showed pharmacokinetic equivalence with FP, but not SM. No significant difference between formulations was seen with either adrenal suppression or hypokalaemia.

Hypothalamic-pituitary-adrenal axis suppression in asthmatic children on inhaled corticosteroids: part 1. Which test should be used?

The effect of inhaled corticosteroids (ICS) on the hypothalamic-pituitary-adrenal axis (HPA) has been regarded as a 'benign physiological response'. A recent survey suggests that adrenal crisis might be more common in asthmatic children on ICS than previously thought. The clinical features of adrenal insufficiency are non-specific and can easily be missed. Accurate biochemical assessment of the axis is therefore mandatory. A review of the literature determined that all basal adrenal function tests, including plasma cortisol profiles, cannot identify which children can respond to stress. There is no evidence to suggests that the degree of the physiological adjustment of the HPA to ICS predicts clinically significant HPA suppression. Only gold standard adrenal function tests can assess the integrity of the whole axis. Of the two available tests, the correctly performed overnight metyrapone test (with ACTH levels) is safe and better by far. The use of cortisol profiles should only be used to demonstrate differences in systemic activity of various ICS and delivery devices. Regulatory bodies should insist on trials that evaluate the HPA with a gold standard adrenal function test before it is declared safe and allowed to be marketed. A re-analysis of studies that have utilized gold standard adrenal function tests only might identify the lowest safe dose and duration of ICS.

A comparison of 2 extrafine hydrofluoroalkane-134a-beclomethasone formulations on methacholine hyperresponsiveness

BACKGROUND

Small airways inflammation is a recognized pathologic component of asthma, and it is postulated that the observed airway-wall remodeling in small airways could be due to uncontrolled inflammation in airways that are not penetrated by conventional inhaled corticosteroids. Thus, extrafine particle formulations of inhaled corticosteroids are of clinical interest.

OBJECTIVE

To compare 2 extrafine solution hydrofluoroalkane-134a formulations of beclomethasone dipropionate (Beclate and Qvar).

METHODS

Fifteen asthmatic patients (mean +/- SEM forced expiratory volume in 1 second [FEV1], 2.62 +/- 0.21 L; provocative concentration of methacholine causing a 20% decrease in FEV1 [PC20], 1.06 +/- 0.58) were randomized to completion in a placebo-controlled, double-blind, crossover manner to receive Beclate or Qvar at doses of 100 or 400 microg/d for 2 weeks, with a 1-week washout period before each randomized treatment. Methacholine hyperresponsiveness was the primary outcome measure.

RESULTS

The 2 formulations were equivalent in terms of predefined equivalence limits of +/- 1 doubling dilution for PC20 at both doses: -0.25 (95% confidence interval [CI], -0.77 to 0.27) doubling dilution difference between the 100-microg doses and a 0.26 (95% CI, -0.29 to 0.82) doubling dilution difference between the 400-microg doses for the difference between Beclate and Qvar, respectively. Both formulations, at either dose, produced a statistically significant (P < .05) reduction in mean exhaled nitric oxide levels: 400 microg/d of Beclate, 14.1 ppb (95% CI, 5.6 to 22.6 ppb); and 400 microg/d of Qvar, 14.2 ppb (95% CI, 6.0 to 22.4 ppb). The higher doses produced a statistically significant (P < .05) reduction in early morning urinary cortisol-creatinine ratio (geometric mean fold suppression: Beclate, 1.48 [95% CI, 1.16 to 1.89]; and Qvar, 1.42 [95% CI, 1.12 to 1.79]). Both formulations significantly improved peak expiratory flow, FEV1, and forced expiratory flow between 25% and 75% of forced vital capacity at the higher doses (P < .05).

CONCLUSIONS

Beclate and Qvar were equivalent for all primary and secondary outcome measures.

Effect of ciclesonide and fluticasone on hypothalamic-pituitary-adrenal axis function in adults with mild-to-moderate persistent asthma

BACKGROUND

Despite their proven efficacy in the treatment and prevention of asthma exacerbations, current inhaled corticosteroids carry safety concerns, especially adrenal suppression. Ciclesonide (hydrofluoroalkane propellant) is a novel inhaled corticosteroid with few, if any, clinical adverse events.

OBJECTIVE

To evaluate the potential effects of ciclesonide therapy on the dynamic cortisol response to sequential low- and high-dose cosyntropin stimulation in adults with mild-to-moderate persistent asthma.

METHODS

This was a double-blind, randomized, placebo-controlled, 12-week study in adults with mild-to-moderate asthma. One hundred sixty-four patients were randomized and treated; 148 patients completed the study. Fluticasone propionate (chlorofluorocarbon propellant) was used as an active comparator. The doses administered were 320 microg of ciclesonide once daily, 320 microg of ciclesonide twice daily, and 440 microg of fluticasone propionate twice daily, all doses ex-actuator.

RESULTS

For both ciclesonide groups, changes in mean low- and high-dose peak serum cortisol levels and in 24-hour urinary free cortisol levels corrected for creatinine were small vs baseline and comparable with placebo. For the fluticasone propionate group, significant reductions vs placebo in serum cortisol levels in response to high-dose cosyntropin stimulation and in 24-hour urinary free cortisol levels were observed. Oral candidiasis rates were 2.5% for 320-microg/d ciclesonide, 2.4% for 640-microg/d ciclesonide, and 22.0% for 880-microg/d fluticasone propionate.

CONCLUSIONS

These findings confirm the safety of ciclesonide therapy, demonstrating that at doses up to 640 microg/d, the drug does not affect sensitive markers of adrenal function.

Adrenal Suppression with Dry Powder Formulations of Fluticasone Propionate and Mometasone Furoate

Mometasone furoate (MF) and fluticasone propionate (FP) are high potency inhaled corticosteroids. The systemic bioavailability of MF is claimed to be negligible, leading to a minimal potential for systemic adverse effects. We assessed the overnight urinary cortisol/creatinine as the primary outcome of adrenal suppression in 21 patients with persistent asthma (mean FEV1 = 91%). Patients were randomized in a crossover fashion to receive 2 weekly consecutive doubling incremental doses of either FP Accuhaler (500, 1,000, and 2,000 microg/day) or MF Twisthaler (400, 800, and 1,600 microg/day). For the 21 per protocol completed patients, there was significant suppression of overnight urinary cortisol/creatinine with high and medium doses of both drugs-as geometric mean fold suppression (95% confidence interval) from baseline: FP 2,000 microg, 1.85 (1.21-2.82, p = 0.002); FP 1,000 microg, 1.45 (1.07-1.96, p = 0.02); MF 1,600 microg, 1.92 (1.26-2.93, p = 0.001); and MF 800 microg, 1.39 (1.04-1.88, p = 0.02). For secondary outcomes of 8:00 A.M. plasma cortisol, serum osteocalcin, and early morning urinary cortisol/creatinine, there was significant suppression with MF and FP at the highest dose. Our data refute the assertion that MF has negligible systemic bioavailability and a lower potential for systemic adverse effects compared with FP.

Systemic activity of inhaled corticosteroid treatment in asthmatic children: corticotrophin releasing hormone test

BACKGROUND

A study was undertaken to assess the function of the hypothalamic-pituitary-adrenal axis (HPA) in a group of asthmatic children before and after treatment with inhaled corticosteroids.

METHODS

Thirty prepubertal patients of mean (SD) age 6.7 (1.8) years were treated with inhaled corticosteroids. All children underwent a corticotrophin releasing hormone (CRH) test with evaluation of serum cortisol and adrenocorticotrophin hormone (ACTH) levels before and after 3 months of treatment. Twenty four hour urine samples were also collected to measure free cortisol (UFC) excretion.

RESULTS

Subjects showed no difference between basal serum cortisol levels (mean change -18; 95% CI -41 to 5; p=0.118) and delta (peak minus basal) levels (mean change -13; 95% CI -38 to 12; p=0.308) before and after treatment, whereas the peak cortisol level (mean change -31; 95% CI -55 to -7; p=0.013) and area under the curve (AUC) (mean change -175; 95% CI -288 to -63; p=0.003) after CRH were significantly lower following treatment. Basal, peak and AUC ACTH were significantly lower after treatment (p<0.05, p=0.004 and p=0.003, respectively), while delta ACTH was similar before and after treatment ((mean change -12; 95% CI - 31 to -7; p=0.199). No significant reduction in 24 hour UFC was observed after the treatment period (before 14.9 (7.1), after 15.0 (11.6); mean change 0.1, 95% CI -5.2 to 5.4; p=0.967). No correlation was found between UFC and any of the parameters of cortisol excretion following the CRH test, either before or after treatment.

CONCLUSIONS

These data suggest that, at the dosage and for the treatment period used, inhaled steroids do not seem to suppress the HPA axis in the majority of patients. The CRH test may be more sensitive than 24 hour UFC and morning plasma cortisol levels in evaluating systemic activity of inhaled corticosteroid treatment.