Adrenal suppression, evaluated by a low dose adrenocorticotropin test, and growth in asthmatic children treated with inhaled steroids

An approach to the management of children with problematic severe asthma

Children with poor asthma control despite high levels of prescribed treatment are described as having problematic severe asthma. Most of these children have steroid sensitive disease which improves with adherence to daily inhaled corticosteroids and after having removed modifiable factors like poor inhalation technique, persistent adverse environmental exposures and psychosocial factors. These children are described as having “difficult-to-treat asthma” while children with persistent symptoms despite above-mentioned factors having been addressed are described as having “severe therapy-resistant asthma”. In this review, we will describe the 6-step approach to the diagnosis and management of a child with problematic severe asthma adopted by The Royal Brompton Hospital (London, UK). The role of a multidisciplinary team is crucial for identification and treatment of modifiable factors and comorbidities in order to avoid invasive examinations and useless pharmacological treatments. The current knowledge on add-on therapies will be discussed.

Effect of long term inhaled corticosteroid therapy on adrenal suppression, growth and bone health in children with asthma

BACKGROUND

Inhaled corticosteroids (ICS) are the most effective treatment for children with persistent asthma. However adverse effects of ICS on Hypothalamo Pituitary Adrenal (HPA) axis, growth and bone metabolism are a concern. Hence the primary objective of this study was to describe the effects of long term inhaled corticosteroid therapy (ICS) on adrenal function, growth and bone health in children with asthma in comparison to an age and sex matched group of children with asthma who were not on long term ICS. Describing the association between the dose of ICS and duration of therapy on the above parameters were secondary objectives.

METHOD

Seventy children with asthma on ICS and 70 controls were studied. Diagnosis of asthma in selected patients was reviewed according to the criteria laid down by GINA 2018 guidelines. The estimated adult heights were interpreted relative to their Mid Parental Height (MPH) range. Serum calcium, alkaline phosphatase and vitamin D levels were analyzed in both groups and cortisol value at 30 min following a low dose short synacthen test was obtained from the study group. The average daily dose of ICS (Beclamethasone) was categorized as low, medium and high (100-200, 200-400, > 400 μg /day) respectively according to published literature.

RESULTS

Heights of all children were within the MPH range. There was no statistically significant difference in the bone profiles and vitamin D levels between the two groups (Ca: p = 0.554, vitamin D: p = 0.187) but vitamin D levels were insufficient (< 50 nmol/l) in 34% of cases and 41% of controls. Suppressed cortisol levels were seen in 24%. Doses of ICS were low, medium and high in 56, 32 and 12% of children respectively. The association between adrenal suppression with longer duration of therapy (p < 0.01) and with increasing dose of ICS (p < 0.001) were statistically significant.

CONCLUSION

ICS had no impact on the growth and bone profiles but its dose and duration were significantly associated with adrenal suppression.

Inhaled corticosteroids in children with persistent asthma: effects of different drugs and delivery devices on growth

BACKGROUND

Inhaled corticosteroids (ICS) are the most effective treatment for children with persistent asthma. Although treatment with ICS is generally considered to be safe in children, the potential adverse effects of these drugs on growth remains a matter of concern for parents and physicians.

OBJECTIVES

To assess the impact of different inhaled corticosteroid drugs and delivery devices on the linear growth of children with persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Trials Register, which is derived from systematic searches of bibliographic databases including CENTRAL, MEDLINE, Embase, CINAHL, AMED and PsycINFO. We handsearched respiratory journals and meeting abstracts. We also conducted a search of ClinicalTrials.gov and manufacturers' clinical trial databases, or contacted the manufacturer, to search for potential relevant unpublished studies. The literature search was initially conducted in September 2014, and updated in November 2015, September 2018, and April 2019.

SELECTION CRITERIA

We selected parallel-group randomized controlled trials of at least three months' duration. To be included, trials had to compare linear growth between different inhaled corticosteroid molecules at equivalent doses, delivered by the same type of device, or between different devices used to deliver the same inhaled corticosteroid molecule at the same dose, in children up to 18 years of age with persistent asthma.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected studies and assessed risk of bias in included studies. The data were extracted by one author and checked by another. The primary outcome was linear growth velocity. We conducted meta-analyses using Review Manager 5.3 software. We used mean differences (MDs) and 95% confidence intervals (CIs ) as the metrics for treatment effects, and the random-effects model for meta-analyses. We did not perform planned subgroup analyses due to there being too few included trials.

MAIN RESULTS

We included six randomized trials involving 1199 children aged from 4 to 12 years (per-protocol population: 1008), with mild-to-moderate persistent asthma. Two trials were from single hospitals, and the remaining four trials were multicentre studies. The duration of trials varied from six to 20 months.One trial with 23 participants compared fluticasone with beclomethasone, and showed that fluticasone given at an equivalent dose was associated with a significant greater linear growth velocity (MD 0.81 cm/year, 95% CI 0.46 to 1.16, low certainty evidence). Three trials compared fluticasone with budesonide. Fluticasone given at an equivalent dose had a less suppressive effect than budesonide on growth, as measured by change in height over a period from 20 weeks to 12 months (MD 0.97 cm, 95% CI 0.62 to 1.32; 2 trials, 359 participants; moderate certainty evidence). However, we observed no significant difference in linear growth velocity between fluticasone and budesonide at equivalent doses (MD 0.39 cm/year, 95% CI -0.94 to 1.73; 2 trials, 236 participants; very low certainty evidence).Two trials compared inhalation devices. One trial with 212 participants revealed a comparable linear growth velocity between beclomethasone administered via hydrofluoroalkane-metered dose inhaler (HFA-MDI) and beclomethasone administered via chlorofluorocarbon-metered dose inhaler (CFC-MDI) at an equivalent dose (MD -0.44 cm/year, 95% CI -1.00 to 0.12; low certainty evidence). Another trial with 229 participants showed a small but statistically significant greater increase in height over a period of six months in favour of budesonide via Easyhaler, compared to budesonide given at the same dose via Turbuhaler (MD 0.37 cm, 95% CI 0.12 to 0.62; low certainty evidence).

AUTHORS' CONCLUSIONS

This review suggests that the drug molecule and delivery device may impact the effect size of ICS on growth in children with persistent asthma. Fluticasone at an equivalent dose seems to inhibit growth less than beclomethasone and budesonide. Easyhaler is likely to have less adverse effect on growth than Turbuhaler when used for delivery of budesonide. However, the evidence from this systematic review of head-to-head trials is not certain enough to inform the selection of inhaled corticosteroid or inhalation device for the treatment of children with persistent asthma. Further studies are needed, and pragmatic trials and real-life observational studies seem more attractive and feasible.

Recovery of hypothalamo-pituitary-adrenal axis suppression during treatment with inhaled corticosteroids for childhood asthma

Objective

To describe recovery of adrenal insufficiency in asthmatic children treated with inhaled corticosteroids (ICS) and cortisol replacement therapy.

Design

Retrospective, observational study.

Patients

A total of 113 patients, 74 male; age 10.4 (3.3–16.5) years; beclomethasone-equivalent ICS dose, 800 μg, (100–1,000), tested by low dose short Synacthen (tetracosactide) test (LDSST), were studied. Test results were classified by basal and peak cortisol concentration: “normal” (basal >100 nmol/L, peak >500 nmol/L), “suboptimal” (basal >100 nmol/L, peak 350–499 nmol/L), “abnormal” (basal <100 nmol/L and/or peak <350 nmol/L). Patients with suboptimal results received hydrocortisone during periods of stress only, and those with abnormal responses received daily hydrocortisone, increased during periods of stress. A total of 73 patients (68%) had ≥2 LDSSTs over 2.2 years (0.2–7.7).

Measurements

Change in cortisol response to repeat LDSST (movement between diagnostic groups, difference in basal and peak cortisol >15% [2× the inter-assay coefficient of variation]), change in BMI and height standard deviation score (SDS).

Results

Baseline test results were abnormal in 17 patients (15%) and all of them had repeat tests. In 13 patients (76%), test results improved (normal in six, suboptimal in seven) and four (24%) remained abnormal. Baseline tests results were suboptimal in 54 patients (48%), of whom 50 (93%) were retested. Repeat tests were normal in 36 patients (72%), remained suboptimal in 11 (22%), and were abnormal in three (6%). Baseline tests results were normal in 42 patients, of whom six patients (14%) were retested. Results remained normal in three (50%), were suboptimal in two (33%), and abnormal in one (17%). Basal and peak cortisol levels increased by >15% in 33/73 (45%) and 42/73 (57%) patients, respectively, and decreased by >15% in 14/73 (19%) and 7/73 (10%), respectively. There was no significant change in height or BMI SDS.

Conclusion

Recovery of adrenal function is common and occurs during continued ICS and cortisol replacement therapy.

Adverse Effects of Nonsystemic Steroids (Inhaled, Intranasal, and Cutaneous): a Review of the Literature and Suggested Monitoring Tool

Inhaled, intranasal, and cutaneous steroids are prescribed by physicians for a plethora of disease processes including asthma and rhinitis. While the high efficacy of this class of medication is well known, the wide range of adverse effects, both local and systemic, is not well elucidated. It is imperative to monitor total steroid burden in its varied forms as well as tracking for possible side effects that may be caused by a high cumulative dose of steroids. This review article highlights the adverse effects of different steroid modalities as well as suggests a monitoring tool to determine steroid totality and side effects.

The effects of inhaled corticosteroids on growth in children

Inhaled corticosteroids (ICS) are recommended as the first-line therapy for children with persistent asthma. These agents are particularly effective in reducing underlying airway inflammation, improving lung function, decreasing airway hyper-reactivity, and reducing intensity of symptoms in asthmatics. Chronic diseases, such as asthma, have growth-suppressing effects independent of the treatment, which inevitably complicates growth studies. One year studies showed a small, dose-dependent effect of most ICS on childhood growth, with some differences across various ICS molecules, and across individual children. Some ICS at the doses studied did not affect childhood growth when rigorous study designs were used. Most studies did not conform completely with the FDA guidance. The data on effects of childhood ICS use on final adult height are conflicting, but one recent well-designed study showed such an effect, clearly warranting additional studies. In spite of these measurable effects of ICS on childhood growth, it is important to understand that the safety profile of all ICS preparations, with focal anti-inflammatory effects on the lung, is significantly better than oral glucocorticoids.

The actual role of sodium cromoglycate in the treatment of asthma--a critical review

INTRODUCTION

Despite international consensus and clearly written guidelines urging wider use of corticosteroids or combinations of inhaled short- and long-acting β-agonists (SABA and LABA) and corticosteroids in persistent asthma, prescribing patterns and compliance rates fall far short of recommendations.

OBJECTIVES

The failure to use steroids more aggressively is due, in part, to their side effects, even with inhaled forms of the drug. There is a role for expanded use of sodium cromolyn in asthma. Its potent anti-inflammatory effects, lack of side effects, and acceptable dosing and method of delivery, as well as its special role in exercise-induced asthma, make it a very suitable choice in the initial therapy for control of asthma.

CONCLUSION

Compared to SABA and LABA, cromoglycates alone are unsuspicious of being used to enhance physical performance.

Bioavailability of inhaled fluticasone propionate via chambers/masks in young children

We determined lung bioavailability of a fluticasone propionate (FP) pressurised metred-dose inhaler (Flovent HFA; GlaxoSmithKline, Research Triangle Park, NC, USA) administered via AeroChamber Plus (Monaghan Medical, Plattsburgh, NY, USA) with Facemask and Babyhaler (GlaxoSmithKline) valved holding chambers (VHCs) using a population pharmacokinetic approach. Children from 1 to <4 yrs of age with stable asthma but a clinical need for inhaled corticosteroid therapy were administered 88 μg FP hydrofluoroalkane (2 × 44 μg) twice daily delivered through the two devices in an open-label, randomised crossover manner for 8 days each. Patients were randomised to one of three sparse sampling schedules for blood collection throughout the 12-h dosing interval on the 8th day of each treatment for pharmacokinetic analysis. The area under the FP plasma concentration-time curve (AUC) was determined for each regimen. 17 children completed the study. The population mean AUC following FP with AeroChamber Plus with Facemask was 97.45 pg·h·mL(-1) (95% CI 85.49-113.32 pg·h·mL(-1)) and with Babyhaler was 51.55 pg·h·mL(-1) (95% CI 34.45-64.46 pg·h·mL(-1)). The relative bioavailability (Babyhaler/AeroChamber Plus) was 0.53 (95% CI 0.30-0.75). Clinically significant differences in lung bioavailability were observed between the devices. VHCs are not interchangeable, as differences in drug delivery to the lung may occur. A population pharmacokinetic approach can be used to determine lung bioavailability of FP.

Patient-reported outcomes in clinical trials of inhaled asthma medications: systematic review and research needs

PURPOSE

To assess the diversity, application, analysis and interpretation of patient-reported outcomes (PROs) in asthma clinical trials.

METHODS

We critically appraised the use of asthma-specific PROs in 87 randomised controlled trials (RCTs) of inhaled asthma medications published during 1985-2006.

RESULTS

A total of 79 RCTs reported PROs, of which 78 (99%) assessed symptom scores and seven (9%) assessed asthma quality of life scores. Only eight (10%) used validated instruments and five (6%) provided clinical interpretation of scores. Due to heterogeneity in the reporting of symptom measures, it is not possible to determine how many discrete symptom assessment instruments have been used. Only 26 (33%) of the RCTs that measured symptom scores reported the scores for follow-up. Limited improvement occurred over time: fewer than 30% of the RCTs used validated PRO measures in any individual year.

CONCLUSION

Numerous validated PRO instruments are available but it is unclear why few are used in asthma clinical trials. Problems include poor reporting, and uncritical analysis and interpretation of PRO scores. Research needs include identifying and recommending a set of PROs for use in asthma clinical research and providing guidance for researchers on the application, analysis and interpretation of PRO measures in clinical trials.

Adrenal responses to low dose synthetic ACTH (Synacthen) in children receiving high dose inhaled fluticasone

BACKGROUND AND AIMS

Clinical adrenal insufficiency has been reported with doses of inhaled fluticasone proprionate (FP) > 400 microg/day, the maximum dose licensed for use in children with asthma. Following two cases of serious adrenal insufficiency (one fatal) attributed to FP, adrenal function was evaluated in children receiving FP outwith the licensed dose.

METHODS

Children recorded as prescribed FP > or = 500 microg/day were invited to attend for assessment. Adrenal function was measured using the low dose Synacthen test (500 ng/1.73 m2 intravenously) and was categorised as: biochemically normal (peak cortisol response > 500 nmol/l); impaired (peak cortisol < or = 500 nmol/l); or flat (peak cortisol < or = 500 nmol/l with increment of < 200 nmol/l and basal morning cortisol < 200 nmol/l).

RESULTS

A total of 422 children had been receiving FP alone or in combination with salmeterol; 202 were not investigated (137 FP within license; 24 FP discontinued); 220 attended and 217 (age 2.6-19.3 years) were successfully tested. Of 194 receiving FP > or = 500 microg/day, six had flat responses, 82 impaired responses, 104 were normal, and in 2 the LDST was unsuccessful. Apart from the index child, the other five with flat responses were asymptomatic; a further child with impairment (peak cortisol 296 nmol/l) had encephalopathic symptoms with borderline hypoglycaemia during an intercurrent illness. The six with flat responses and the symptomatic child were all receiving FP doses of > or = 1000 microg/day.

CONCLUSION

Overall, flat adrenal responses in association with FP occurred in 2.8% of children tested, all receiving > or = 1000 microg/day, while impaired responses were seen in 39.6%. Children on above licence FP doses should have adrenal function monitoring as well as a written plan for emergency steroid replacement.

Inhaled corticosteroids versus sodium cromoglycate in children and adults with asthma

BACKGROUND

Inhaled corticosteroids (ICS) and sodium cromoglycate (SCG) have become established as effective controller medications for children and adults with asthma, but their relative efficacy is not clear.

OBJECTIVES

To compare the relative effectiveness and adverse effects of ICS and SCG among children and adults with chronic asthma.

SEARCH STRATEGY

Systematic search of the Cochrane Airways Group's special register of controlled trials (to Feb. 2004), hand searches of the reference lists of included trials and relevant review papers, and written requests for identification of additional trials from pharmaceutical manufacturers.

SELECTION CRITERIA

Randomized controlled trials comparing the effect of ICS with SCG in children and adults with chronic asthma.

DATA COLLECTION AND ANALYSIS

All studies were assessed independently for eligibility by three review authors. Disagreements were settled by consensus. Trial authors were contacted to supply missing data or to verify methods. Eligible studies were abstracted and fixed- and random-effects models were implemented to pool studies. Separate analyses were conducted for paediatric and adult studies. Subgroup analyses and meta-regression models were fit to explore heterogeneity of lung function outcomes by type of RCT, category of ICS or SCG dosage, asthma severity of participants, and study quality on outcomes.

MAIN RESULTS

Of 67 identified studies, 17 trials involving 1279 children and eight trials involving 321 adults with asthma were eligible. Thirteen (76%) of the paediatric studies and six (75%) of the adult studies were judged to be high quality. Among children, ICS were associated with a higher final mean forced expiratory volume in 1 second [FEV1] (weighted mean difference [WMD] 0.07 litres, 95% confidence interval [CI] 0.02 to 0.11) and higher mean final peak expiratory flow rate [PEF] (WMD 17.3 litres/minute, 95% CI 11.3 to 23.3) than SCG. In addition, ICS were associated with fewer exacerbations (WMD -1.18 exacerbations per year, 95% CI -2.15 to - 0.21), lower asthma symptom scores, and less rescue bronchodilator use than SCG. There were no group differences in the proportion of children with adverse effects. Among adults, ICS were similarly associated with a higher mean final FEV1 (WMD 0.21 litres, 95% CI 0.13 to 0.28) and a higher final endpoint PEF (WMD 28.2 litres/minute, 95% CI 18.7 to 37.6) than SCG. ICS were also associated with fewer exacerbations (WMD -3.30 exacerbations per year, 95% CI -5.62 to -0.98), lower asthma symptom scores among cross-over trials but not parallel trials, and less rescue bronchodilator use than SCG. There were no differences in the proportion of adults with adverse effects. In subgroup analyses involving lung function measures, paediatric and adult studies judged to be of high quality had results consistent with the overall results. Lung function measures in children were higher in studies with medium BDP-equivalent steroid dosages than low BDP-equivalent dosages, while adult studies could not be compared by steroid dosage since they all incorporated similar dosages. There were no significant differences in lung function by the asthma severity of participants for adult or child studies.

AUTHORS' CONCLUSIONS

ICS were superior to SCG on measures of lung function and asthma control for both adults and children with chronic asthma. There were few studies reporting on quality of life and health care utilization, which limited our ability to adequately evaluate the relative effects of these medications on a broader range of outcomes. Although there were no differences in adverse effects between ICS and SCG, most trials were short and may not have been of sufficient duration to identify long-term effects. Our results support recent consensus statements in the U.S. and elsewhere that favour the use of ICS over SCG for control of persistent asthma.

Polycystic ovary syndrome in adolescence

Polycystic ovary syndrome (PCOS) is a syndrome of variable combinations of menstrual irregularity, hirsutism or acne, and obesity. It can be diagnosed in adolescence and has early childhood antecedents. PCOS is the single most common endocrine cause of an ovulatory infertility and a major risk factor for the metabolic syndrome and, in turn, development of type 2 diabetes mellitus in women. Thus, it appears that PCOS increases a woman's risk of developing cardiovascular disease. Therefore, identifying girls at risk for PCOS and implementing treatment early in the development of PCOS may be an effective means of preventing some of the long-term complications associated with this syndrome. This article reviews the definition, clinical features, diagnosis, and treatment of PCOS.

Systematic review of the dose-response relation of inhaled fluticasone propionate

AIMS

To examine the dose-response relation of inhaled fluticasone for both efficacy and adrenal function in children with asthma.

METHODS

Systematic review of double blind randomised dose-response studies of fluticasone in children of at least 4 weeks duration.

MAIN OUTCOME MEASURES

FEV1, morning peak expiratory flow, night awakenings, beta agonist use, major exacerbations, 12 or 24 hour urinary cortisol, peak plasma cortisol post-stimulation.

RESULTS

Seven studies of 1733 children with asthma met the inclusion criteria for efficacy. The dose-response curve for each efficacy outcome measure suggested that the response began to plateau between 100 and 200 microg per day with additional efficacy at the 400 microg per day dose shown in one study of severe asthmatics. Five studies of 1096 children with asthma met the inclusion criteria for assessment of adrenal function. The largest placebo controlled study of 437 children reported no difference in 24 hour urinary cortisol between placebo and fluticasone at doses of 100 and 200 microg per day. The non-placebo controlled study of 528 children reported significant suppression of overnight urinary cortisol levels with fluticasone at 400 compared with 200 microg per day.

CONCLUSIONS

There is insufficient data to determine the dose-response of fluticasone in children at doses >400 microg per day. The dose-response curve for fluticasone appears to plateau between 100 and 200 microg per day for efficacy. There was additional efficacy at the 400 microg per day dose in children with severe asthma; however there was evidence of adrenal suppression at this dose.

Monitoring growth in asthmatic children treated with high dose inhaled glucocorticoids does not predict adrenal suppression

AIMS

To determine whether routine outpatient monitoring of growth predicts adrenal suppression in prepubertal children treated with high dose inhaled glucocorticoid.

METHODS

Observational study of 35 prepubertal children (aged 4-10 years) treated with at least 1000 microg/day of inhaled budesonide or equivalent potency glucocorticoid for at least six months. Main outcome measures were: changes in HtSDS over 6 and 12 month periods preceding adrenal function testing, and increment and peak cortisol after stimulation by low dose tetracosactrin test. Adrenal suppression was defined as a peak cortisol < or =500 nmol/l.

RESULTS

The areas under the receiver operator characteristic curves for a decrease in HtSDS as a predictor of adrenal insufficiency 6 and 12 months prior to adrenal testing were 0.50 (SE 0.10) and 0.59 (SE 0.10). Prediction values of an HtSDS change of -0.5 for adrenal insufficiency at 12 months prior to testing were: sensitivity 13%, specificity 95%, and positive likelihood ratio of 2.4. Peak cortisol reached correlated poorly with change in HtSDS (rho = 0.23, p = 0.19 at 6 months; rho = 0.33, p = 0.06 at 12 months).

CONCLUSIONS

Monitoring growth does not enable prediction of which children treated with high dose inhaled glucocorticoids are at risk of potentially serious adrenal suppression. Both growth and adrenal function should be monitored in patients on high dose inhaled glucocorticoids. Further research is required to determine the optimal frequency of monitoring adrenal function.

Safety of the newer inhaled corticosteroids in childhood asthma

Inhaled corticosteroids (ICS) remain a vital part of the management of persistent asthma, but concerns have been raised about their potential adverse effects in children. This review examines the safety data on three new ICS - fluticasone propionate, mometasone, and extrafine beclomethasone in hydrofluoroalkane (HFA-134a) propellant (QVAR The use of tradenames is for product identification purposes only and does not imply endorsement. formulation) in relation to the older corticosteroids. Topical adverse effects such as thrush and dysphonia are rare, but dental erosion is a possibility with powder forms of ICS because of their low pH. Thus, it is important to stress mouth rinsing after administration and maintaining good dental hygiene to minimize this risk. Biochemical adrenal suppression can be readily demonstrated, particularly with high doses of all ICS. The clinical relevance of this was uncertain in the past, but there have now been >50 reported cases of acute adrenal crises in children receiving ICS, most of whom were on fluticasone propionate. In order to minimize the risk of symptomatic adrenal suppression, it is important to back-titrate the ICS dose and alert families of children receiving high-dose ICS of this potential adverse effect. A pediatric endocrine opinion should be sought if adrenal suppression is suspected. The older ICS cause temporary slowing of growth velocity, but the limited data available do not show any significant compromise of final adult height. The effect on growth of fluticasone propionate may not be as great as with the older ICS, but the studies have been short term and only used low doses of fluticasone propionate. There have been case reports of growth suppression in children receiving high doses of fluticasone propionate. The limited studies performed on the effect of ICS on bone mineral density in children did not show any adverse effects, but there may be an increased risk of fractures. Hydrofluoroalkane beclomethasone (QVAR) is essentially the same drug as chlorofluorocarbon beclomethasone, but with double the lung deposition owing to the smaller particle size. Thus, it could be expected that any adverse effects seen with chlorofluorocarbon beclomethasone would be the same with hydrofluoroalkane beclomethasone. However, some of the published data, particularly in adults, suggest that hydrofluoroalkane beclomethasone may be less systemically active than chlorofluorocarbon beclomethasone, even at equipotent doses. As yet, there are no long-term data on mometasone, but initial studies in adults suggest there may be less suppression of the hypothalamic-pituitary-adrenal axis, although further studies are required, particularly in children.ICS will remain a cornerstone in the management of persistent pediatric asthma, provided that the diagnosis of asthma is secure. It is very important to use ICS appropriately and to ensure the lowest possible doses are used to achieve symptom control, thus minimizing the risk of serious adverse effects.

Inhaled corticosteroids in childhood asthma: long-term effects on growth and adrenocortical function

Inhaled corticosteroids (ICS) are the most potent of all the available inhaled treatments, and are effective medications for long-term control of asthma. However, their use in children is limited by the risk of systemic adverse effects. Although results reported in the literature on the adverse effects of ICS are conflicting and often restricted to a small number of cases with a limited follow-up, most of them show an early decrease in growth velocity without significant influence on final adult height. Partial adrenal suppression has also been demonstrated in children treated with ICS for more than 2 months. Only children with mild persistent, moderate, or severe asthma not controlled by non-corticosteroid drugs should be treated with ICS for long periods. The dose of ICS must be individually adjusted to minimize the possible adverse effects on growth, and all children with asthma receiving long-term treatment with ICS must be regularly evaluated for growth impairment, which may necessitate dose reduction or drug replacement.

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.

Safety of inhaled and intranasal corticosteroids: lessons for the new millennium

Although inhaled and intranasal corticosteroids are first-line therapy for asthma and allergic rhinitis, there has recently been an increasing awareness of their propensity to produce systemic adverse effects. The availability of more potent and lipophilic corticosteroids and new chlorofluorocarbon (CFC)-free formulations has focused attention on these safety issues. The main determinant of systemic bioavailability of these drugs is direct absorption from the lung or nose, where there is no first-pass inactivation. Consequently, the systemic bioavailability of inhaled corticosteroids is greatly influenced by the efficiency of the inhaler device. Thus, when comparing different inhaled corticosteroids it is imperative to consider the unique drug/device interaction. The pharmacokinetic profile is important in determining the systemic bioactivity of inhaled and intranasal corticosteroids. For highly lipophilic drugs, such as fluticasone propionate or mometasone furoate, there is preferential partitioning into the systemic tissue compartment, and consequently a large volume of distribution at steady state. In contrast, drugs with lower lipophilicity, such as triamcinolone acetonide or budesonide, have a smaller volume of distribution. The systemic tissue compartment may act as a slow release reservoir, resulting in a long elimination half-life for the lipophilic drugs. For intranasal corticosteroids, a high degree of lipophilicity diminishes water solubility in mucosa and therefore increases the amount of drug swept away by mucociliary clearance before it can gain access to tissue receptor sites. This may reduce the anti-inflammatory efficacy in the nose, but might also reduce the propensity for direct systemic absorption from the nasal cavity. The hydrofluoroalkane (HFA) formulations of beclomethasone dipropionate are solutions and exhibit a much higher respirable fine particle dose than do the CFC formulations. Dose-response studies with one of the HFA formulations have shown therapeutic equivalence at half the dosage, with little evidence of adrenal suppression at dosages up to 800 microg/day. A lack of similar studies for another of the available HFA formulations has led to a discrepancy in the recommendations for equivalence. Although in vitro studies have pointed to a similar fine particle distribution for the HFA and CFC formulations of fluticasone propionate, this is not supported by in vivo data for lung bioavailability, suggesting that care will be required when switching these formulations. Prescribers of inhaled and intranasal corticosteroids should be aware of the potential for long term systemic effects. The safest way to use these drugs is to 'step-down' to achieve the lowest possible effective maintenance dosage.