R-134a (1,1,1,2-Tetrafluoroethane) Inhalation Induced Reactive Airways Dysfunction Syndrome.

R-134a (1,1,1,2-tetrafluoroethane) is widely used as a refrigerant and as an aerosol propellant. Inhalation of R-134a can lead to asphyxia, transient confusion, and cardiac arrhythmias. We report a case of reactive airways dysfunction syndrome secondary to R-134a inhalation. A 60-year-old nonsmoking man without a history of lung disease was exposed to an air conditioner refrigerant spill while performing repairs beneath a school bus. Afterward, he experienced worsening shortness of breath with minimal exertion, a productive cough, and wheezing. He was also hypoxic. He was admitted to the hospital for further evaluation. Spirometry showed airflow obstruction with an FEV1 1.97 L (45% predicted). His respiratory status improved with bronchodilators and oral steroids. A repeat spirometry 2 weeks later showed improvement with an FEV1 2.5 L (60% predicted). Six months after the incident, his symptoms had improved, but he was still having shortness of breath on exertion and occasional cough.

Use of Ozone-Depleting Substances. Direct final rule.

The Food and Drug Administration (FDA, the Agency, or we) is amending its regulation on uses of ozone-depleting substances (ODSs), including chlorofluorocarbons (CFCs), to remove the designation for certain products as "essential uses" under the Clean Air Act. Essential-use products are exempt from the ban by FDA on the use of CFCs and other ODS propellants in FDA-regulated products and from the ban by the Environmental Protection Agency (EPA) on the use of ODSs in pressurized dispensers. The products that will no longer constitute an essential use are: Sterile aerosol talc administered intrapleurally by thoracoscopy for human use and metered-dose atropine sulfate aerosol human drugs administered by oral inhalation. FDA is taking this action because alternative products that do not use ODSs are now available and because these products are no longer being marketed in versions that contain ODSs.

The president speaks: prevention is best: lessons from protecting the ozone layer.

The Montreal Protocol was signed 25 years ago. As a result, the irreversible destruction of the ozone layer was prevented. However, stratospheric ozone will not recover completely until 2060 and the consequent epidemic in skin cancer cases will persist until 2100. Many millions of patients with asthma and chronic obstructive pulmonary disease have safely switched from chlorofluorocarbon (CFC)-powered metered-dose inhalers (MDIs) to either hydrofluorocarbon (HFC) or DPIs. China will be the last country to phase out CFCs by 2016. HFCs are global warming gases which will be controlled in the near future. HFCs in MDIs may be phased out over the next 10-20 years.

Nitrogenous subcutaneous emphysema caused by spray application of fibrin glue during retroperitoneal laparoscopic surgery.

We report a case of a patient treated by retroperitoneoscopic partial nephrectomy who developed nitrogenous subcutaneous emphysema (SCE) as a complication. The use of a nitrogen gas-pressured fibrin tissue adhesive applied as a spray caused excessively increased pressure in the closed retroperitoneal space and resulted in widespread SCE with protracted clinical course. To the best of our knowledge, this is the first report of nitrogenous SCE associated with pneumoperitoneum. The clinical significance of nitrogenous SCE is emphasized, and the risks associated with the use of fibrin glue as a spray during laparoscopic surgery are discussed.

Sustainability in Inhaled Drug Delivery.

Asthma and chronic obstructive pulmonary disease (COPD) are amongst the most common chronic diseases worldwide, and are largely preventable by improving the quality of the air we breathe. The most commonly deployed treatment, the metered dose inhaler (MDI), uses hydrofluorocarbon propellants, which are powerful greenhouse gases that contribute disproportionately to the climate crisis. Alternative treatment strategies are required if we are to avoid contributing to the worst effects of climate change. These strategies include promoting non-pharmacological therapies like smoking cessation and pulmonary rehabilitation; empowering patients to gain better disease control through written management plans and encouraging preventer, rather than reliever therapies. Pharmacological strategies include: improving inhaler technique and spacer use; minimising propellant release by using smaller volume MDIs and simpler dosing regimes; dose counters to prevent waste; switching to low global warming potential inhalers; and inhaler recycling. There are also opportunities to improve disease control alongside reduced greenhouse gas emissions, including better matching of patients' devices to inhaler technique rather than defaulting to MDIs, stopping unnecessary inhaled steroids in COPD and maintenance and reliever therapy in asthma. New, lower global warming potential propellants are on the horizon, and their introduction could offer a golden opportunity to enhance MDIs usability and sustainability by making them refillable, integrating whistles to optimise inhalation technique, adding integrated caps, optimising materials for recycling and adding dose counters to all MDIs.

Intentional self-inflicted and peer-inflicted aerosol skin injuries called 'frosties': Cohort series and systematic literature review.

BACKGROUND AND OBJECTIVES: 'Frosties' are deliberate cold skin burns caused by an aerosol device. The aim of this article was to examine our own cohort, and those previously published, to identify the key features of patients presenting with frosties and inform appropriate early clinical interventions. METHOD: We compared cases in our dataset that occurred between 1 January 2013 and 30 June 2017 with those reported in the literature, focusing on seven domains: sex, age at injury, days to presentation, first aid, depth of injury and outcome. RESULTS: The median patient age was 13 years; 70.5% were female. Adequate first aid was not reported in any patient. Where recorded, the median time to presentation to a health service was six days. Where severity of injury was recorded, 13 of 37 cases (35.1%) were full thickness, and 10 patients received a split thickness skin graft. Two subgroups were identified: cluster injuries and psychological distress. DISCUSSION: Cluster injuries occur as the result of a mutual 'test of courage'. Solo injuries may point to underlying psychological distress. Frosties frequently result in significant burn injuries and often require skin grafting. The severity of frosties is underappreciated and, as a consequence, treatment, through first aid or presentation to a health service, is delayed or absent. General practitioners should be familiar with the appearance of frosties in order to identify them in unrelated consultations.

A modified prescription-event monitoring study to assess the introduction of Seretide Evohaler in England: an example of studying risk monitoring in pharmacovigilance.

INTRODUCTION: Monitoring was required for the introduction of non-chlorofluorocarbon (CFC) propellants in metered dose inhalers (MDIs) to ensure that there were no unexpected adverse events due to the new products. A postmarketing surveillance study has been conducted to evaluate the introduction of the MDI Seretide Evohaler (hydrofluoroalkane-134a inhaler containing salmeterol and fluticasone propionate). OBJECTIVES: To summarise the modified prescription-event monitoring (PEM) study conducted to evaluate the introduction of Seretide Evohaler and discuss the relevance of this type of study towards pharmacovigilance risk-management planning. METHODS: Modified PEM methodology was used to examine the introduction of Seretide Evohaler into general practice in England. Patients were identified from the first National Health Service prescriptions dispensed in England for Seretide Evohaler. One postal questionnaire was sent to the prescribing doctor, requesting demographic information, severity of the indication, concomitant medication for this condition, smoking history, event data 3 months prior to and 3 months after the first prescription for Seretide Evohaler and also reason for stopping if it had been stopped. Pregnancies, deaths and selected events were followed up. Incidence density ratios were calculated to compare event rates 3 months prior to and 3 months after the introduction of Seretide Evohaler. A matched cohort analysis examined oral corticosteroid use and hospital admissions between the pre- and post-exposure periods. RESULTS: The cohort comprised 13,464 patients prescribed Seretide Evohaler, with a response rate of 62%. There was no significant difference in the length of courses of oral corticosteroid use when the pre- and post-exposure periods were compared. A matched cohort analysis showed there was no increase in the use of oral corticosteroids (relative risk [RR] 0.95; 95% CI 0.90, 0.99) or hospital admissions in the post-exposure period (RR 0.87; 95% CI 0.73, 1.04). When the number of patients with events were compared for the periods 3 months before and 3 months after exposure, fewer events were reported in the post-exposure period. There were 64 patients who experienced adverse events within an hour of using Seretide Evohaler, including one report of paradoxical bronchospasm and one of myocardial infarction with fatal outcome that were both assessed as possibly related to treatment. DISCUSSION: The results of the study suggest that the introduction of Seretide Evohaler was generally well tolerated. The modified methodology has allowed a comparison of the event rates before and after the introduction of this CFC-free inhaler into general practice.

Efficacy of beclomethasone dipropionate HFA 200 microg once daily in chronic obstructive pulmonary disease and bronchial asthma.

The efficacy and safety of once-daily beclomethasone dipropionate (BDP; 200 microg), in combination with the propellant hydrofluoroalkane-134a (HFA) was compared with that of budesonide turbuhaler (BUD-TH) 400 microg twice daily and fluticasone propionate inhaler (FP-IH) 250 microg twice daily in 40 patients with bronchial asthma or chronic obstructive pulmonary disease. All patients had used inhaled corticosteroids for at least 1 month. On randomization, 20 patients were switched to HFA-BDP and 20 patients remained on their existing BUD-TH or FP-IH treatment. After 8 weeks, HFA-BDP demonstrated a greater improvement in spirometric values, respiratory symptoms and beta2-agonist use. No significant local adverse effects were observed. Blood cortisol levels remained in the normal range in both groups. We conclude that HFA-BDP (200 microg once-daily) offered more benefit in terms of clinical and spirometry indices than BUD-TH (400 microg twice daily) or FP-IH (250 microg twice daily) in patients with moderate asthma and chronic obstructive pulmonary disease.

Efficacy and safety of ipratropium bromide/salbutamol sulphate administered in a hydrofluoroalkane metered-dose inhaler for the treatment of COPD.

BACKGROUND: The use of chlorofluorocarbons (CFCs) has contributed to the depletion of the stratospheric ozone layer resulting in serious health concerns. Ipratropium bromide/salbutamol sulphate CFC-pressurized metered-dose inhalers (IB/SAL-CFC pMDI) have been in widespread use for many years without any apparent ill consequences. This combination has now been reformulated using the hydrofluoroalkane (HFA) propellant. This study sought to establish the clinical noninferiority of a new HFA-containing IB/SAL pMDI to the conventional IB/SAL-CFC pMDI in subjects with mild/moderate COPD. METHODS: This was a randomized, double-blind, parallel-group, multicenter study in two consecutive periods: a 14-day run-in period followed by a 85-day treatment period. Eligible mild-to-moderate stable COPD subjects aged 40-75 years were enrolled into the study and entered the run-in period during which subjects withdrew all the bronchodilators, except for salbutamol as rescue medication. Subjects were randomized to 85 days treatment with either IB/SAL-HFA or IB/SAL-CFC, 20 µg qid. RESULTS: Of the 290 randomized patients, 249 completed the study. The primary efficacy variable was the change in forced expiratory volume in one second from predose to 60 minutes after dosing on day 85. At the end of the treatment period, the adjusted mean change in forced expiratory volume in one second at 60 minutes was 123 mL in the IB/SAL-HFA pMDI group and 115 mL in the IB/SAL-CFC pMDI group. Because the lower limit of the 95% confidence interval for the between-group difference (-62 mL) was well within the noninferiority margin (-100 mL), the HFA formulation was deemed clinically noninferior to the CFC formulation. This finding was supported by secondary efficacy assessments. Both formulations of IB/SAL were well tolerated during the prolonged multiple dosing. CONCLUSION: It is concluded that IB/SAL-HFA pMDI provides effective bronchodilation of similar degree to that achieved with IB/SAL-CFC pMDI. Therefore, IB/SAL-HFA pMDI is a valuable alternative to IB/SAL-CFC pMDI.

A proposed mechanism for cardiac sensitisation: electrophysiological study of effects of difluorodichloromethane and adrenaline on different types of cardiac preparations isolated from sheep hearts.

Difluorodichloromethane (FC12) inhaled at high concentrations sensitises, as do numerous other volatile organic compounds, mammalian heart to adrenaline induced arrhythmias. In this study three types of cardiac tissue (spontaneously beating sinusal and Purkinje preparations and stimulated Purkinje fibres) were isolated from sheep hearts and perfused for electrophysiological recording to examine the effect of FC 12. Preparations were perfused alternately with a control solution of physiological fluid and a trial solution with dissolved FC 12, the partial pressure of oxygen remaining identical. Sensitisation to adrenaline was studied by injecting adrenaline at a dose causing a notable effect without producing arrhythmias in the control preparations. Examination of transmembrane potential recordings confirmed that FC 12 inhibits sinus node pacemaker stimulation by adrenaline. Conversely, the adrenaline induced acceleration of latent pacemakers in certain types of Purkinje fibres appeared to be potentialised by FC 12. The various types of arrhythmia observed in vitro were explained by the effect of FC 12 on cell membranes, an affect which can oppose or favour that of adrenaline. These phenomena explain the arrhythmias observed in isolated hearts or whole animal preparations and permit a better understanding of the mechanism involved in cardiac sensitisation to adrenaline induced arrhythmia, a mechanism in which variability in time and location is the essential factor in the FC 12 effect.

Safety of long-term treatment with HFA albuterol.

BACKGROUND: Chlorofluorocarbons (CFCs) used as propellants in metered-dose inhalers deplete stratospheric ozone, which results in serious public health concerns. Albuterol has been reformulated in the non-ozone-depleting propellant, hydrofluoroalkane-134a (HFA albuterol). OBJECTIVES: The primary objective was to compare the safety of HFA albuterol to an albuterol product formulated in chlorofluorocarbon propellants (CFC albuterol) during 1 year of treatment in asthmatics. Bronchodilator efficacy of the two products was assessed as a secondary objective. METHODS: The results from two open-label, parallel-group trials of similar design in asthmatics requiring short-acting beta-agonists for symptom control were combined. Patients took two puffs bid of either HFA albuterol or CFC albuterol for 1 year. Additional puffs of study drug were allowed as needed to control asthma symptoms. Adverse events were recorded at clinic visits. Patients self-administered study drug at quarterly visits and underwent serial spirometry during a 6-h period postdose. Bronchodilator efficacy variables, based on FEV1 response to study drug, were proportion of responders, time to onset of effect, peak percent change, time to peak effect, duration of effect, and area under the curve. Differences between products and changes over time in efficacy variables were assessed using an analysis of variance model. Regression analyses with FEV1 as a covariate were performed post-hoc to analyze changes in bronchodilator efficacy over time. RESULTS: Demographic and baseline characteristics were similar for patients receiving HFA albuterol (n = 337) and CFC albuterol (n = 132). Total reported adverse events were similar for the two treatments. Differences in only four individual adverse events were noted: the HFA albuterol group reported more gastroenteritis and dizziness; the CFC albuterol group reported more epistaxis and expectoration. Adverse events attributed to study drug use were infrequent. No serious adverse events were related to study drug use. Predose FEV1 at quarterly visits increased to a small extent in both groups from month 0 to month 12. The bronchodilator efficacy of HFA albuterol was comparable to that of CFC albuterol at the quarterly visits, but decreased from baseline for both products over the 12 months of treatment. Use of inhaled corticosteroids, nasal corticosteroids, or theophylline did not explain the increase in predose FEV1 over time and did not protect patients from developing reduced bronchodilator efficacy by month 12. The change in predose FEV1 did not entirely account for the reduced bronchodilator efficacy over time. CONCLUSIONS: HFA albuterol has a safety profile similar to that of CFC albuterol during chronic, scheduled use, and both drugs are well tolerated. HFA albuterol and CFC albuterol provided comparable bronchodilator efficacy, but bronchodilator efficacy decreased for both products with 1 year of use.

Acute safety of beclomethasone dipropionate in a new CFC-free propellant system in asthmatic patients.

Hydrofluoroalkane-134a (HFA-134a) is a new chlorofluorocarbon (CFC)-free propellant for use in metered dose inhalers. It provides a more environmentally friendly alternative to CFC propellants because it does not contain chlorine which is responsible for ozone depletion by CFCs. Beclomethasone dipropionate (BDP) is widely used for inhalation asthma therapy and is most commonly delivered by a CFC propellant system. The present study evaluated the acute safety of BDP formulated with the new propellant (HFA-134a BDP) compared with BDP in a CFC-11/12 formulation by measuring the acute bronchial response in asthmatic patients. The study was conducted as a randomized, single-blind, placebo-controlled, four-period cross-over trial. Asthmatic patients received eight inhalations of four treatment regimens (HFA-134a BDP, 1600 mg total dose; CFC-11/12 BDP, 2000 mg total dose; HFA-134a placebo and CFC-11/12 placebo) in random order over four study days. Forced expired volume in 1 s (FEV1) was measured before and 2, 10, 20, 40 and 60 min after inhalation of the study treatments. The number of coughs was counted from the start of the first inhalation to 60 s after the last inhalation. There were no statistically significant differences between the treatment groups for changes in FEV1, for the number of coughs or for the occurrence or severity of bronchoconstriction. In asthmatic patients withholding bronchodilators, the new HFA-134a BDP propellant system proved as safe and was as well tolerated as the current CFC-11/12 BDP system. The two propellant systems without active drug were also equally well tolerated.

Equivalence of as-required salbutamol propelled by propellants 11 and 12 or HFA 134a in mild to moderate asthmatics. German Study Group.

This randomized, double-blind, parallel-group study compared the efficacy and tolerability of as-required salbutamol 100 microg administered from either a chlorofluorocarbon (CFC) pressurized metered dose inhaler (pMDI; Ventolin) or from a non-CFC hydrofluoroalkane (HFA) 134a pMDI (Ventolin CFC-free) in patients with mild to moderate asthma. All patients (n = 423) continued with their standard asthma therapy, and recorded their daily use of study medication, morning and evening peak expiratory flow (PEF) and symptom scores, throughout the 4-week treatment period. Clinic lung function was measured at 2-week intervals. The median daily use of inhaled study medication remained constant at four actuations per day throughout the study in both treatment groups and statistical analysis indicated that the two formulations were equivalent. Small improvements in both treatment groups were reported in mean morning and evening PEF, clinic forced expiratory volume in 1 sec and clinic PEF and there were no significant differences between the two groups. Both formulations were well tolerated. This study indicates that as-required salbutamol 100 microg administered via a HFA 134a pMDI is as effective and safe as the currently available CFC-propelled formulation.

Clinical efficacy and safety of fluticasone propionate 1 mg per day administered via a HFA 134a pressurized metered dose inhaler to patients with moderate to severe asthma. International study group.

This multi-national, double-blind, randomized, parallel-group study compared the efficacy and tolerability of fluticasone propionate 500 microg twice daily propelled either by the non-chlorofluorocarbon (CFC) propellant, hydrofluoroalkane (HFA) 134a, or the CFC propellants 11 and 12 used in the established pressurized metered dose inhaler (pMDI). The study period was 12 months and involved 412 subjects with moderate to severe asthma (HFA 134a pMDI: n = 203; CFC pMDI: n = 209). For the first 3 months, subjects kept a daily record card and attended the clinic every 4 weeks. Thereafter, they kept daily diaries for 2 weeks before each clinic assessment, which were performed at the end of 6, 9 and 12 months. Mean morning peak expiratory flow (PEF) increased during the first week in both treatment groups. By the end of week 12 the adjusted mean increase from baseline in morning PEF was 21 and 23 l min(-1) in the HFA 134a and CFC pMDI groups, respectively, and this increase was maintained throughout the 12-month study period. Similar improvements were detected in other diary card parameters and in clinic lung function measurements. The two groups were shown to be clinically equivalent in terms of all efficacy variables and there were no differences in tolerability. There were few reports of low serum cortisol levels during the 12-month study period, and serum cortisol levels were similar at baseline and after 12 weeks and 12 months of treatment in the two groups. In conclusion, the new HFA 134a fluticasone propionate pMDI is as effective and safe as the established CFC fluticasone propionate pMDI when used at a dosage of 1 mg day(-1).

Clinical efficacy and safety of fluticasone propionate 250 microg twice daily administered via a HFA 134a pressurized metered dose inhaler to patients with mild to moderate asthma. French study group.

This study compared the efficacy and safety of the fluticasone propionate 125 microg pressurized metered dose inhaler (pMDI) propelled by either hydrofluoroalkane (HFA) 134a or chlorofluorocarbon (CFC) propellants, in adult patients with asthma. HFA 134a is a non-ozone depleting propellant used as a replacement for the CFC propellants 11 and 12 which are being phased out in accordance with the Montreal Protocol. Three hundred and eighty patients with mild to moderate asthma and 'room for improvement' in their treatment were randomized to receive fluticasone propionate 250 microg twice daily via pMDIs propelled by either CFC propellants 11 and 12 (n = 195) or HFA 134a (n = 185). Fluticasone propionate significantly improved lung function over the 4-week treatment period in both treatment groups. The improvement in mean morning peak expiratory flow (PEF) after 7 days of treatment was approximately 12 l min(-1) in both groups, rising to approximately 22 l min(-1) at the end of the 4-week treatment period. The adjusted mean difference between the two formulations over weeks 1-4 was -1 l min(-1) (90% confidence interval: -7, 5 l min(-1)), confirming their equivalence. Clinical comparability was also demonstrated with respect to secondary efficacy variables, including daily symptom scores, evening PEF and clinic visit expiratory measurements. There were no clinically relevant differences in adverse events or serum cortisol levels between the two groups. The fluticasone propionate 125 microg HFA 134a pMDI is an effective and well tolerated product and is a suitable replacement for the fluticasone propionate 125 microg CFC pMDI at a microgram equivalent dose.

Clinical efficacy and safety of fluticasone propionate 1 mg twice daily administered via a HFA 134a pressurized metered dose inhaler to patients with severe asthma. U.K. study group.

A randomized, double-blind, cross-over study was conducted to assess the efficacy and safety of fluticasone propionate 1 mg twice daily administered via a pressurized metered dose inhaler (pMDI) containing the new non-chlorofluorocarbon (CFC) propellant (HFA 134a), or the established CFC propellants 11 and 12 in patients with severe asthma. The study comprised a 2-week run-in period followed by two 6-week treatment periods, with no washout period in between. One hundred and nineteen symptomatic adult patients with severe asthma, who were receiving inhaled beclomethasone 2-4 mg day(-1) or equivalent, were randomized to treatment. Patients were randomized to one of two sequence groups (sequence 1: HFA 134a pMDI then CFC pMDI or sequence 2: CFC pMDI then HFA 134a pMDI). The sequence groups differed with respect to mean peak expiratory flow (PEF) at baseline; however, the magnitude of the increase in PEF from baseline during treatment was similar in the two sequence groups. Mean PEF at baseline was 334 l min(-1) in sequence group 1 (HFA 134a-->CFC pMDI) and this increased to 357 l min(-1) and 366 l min(-1) during treatment with the HFA 134a and CFC pMDI, respectively. In sequence group 2 (CFC-->HFA 134a pMDI) mean PEF at baseline was 297 l min(-1) and this increased to 336 l min(-1) and 328 l min(-1) during treatment with the HFA 134a and CFC pMDI, respectively. Based on an overall analysis of the two treatment groups at week 6, equivalence was demonstrated; the mean treatment difference (HFA 134a-CFC pMDI) in morning PEF was 0 l min(-1) (90% confidence interval (CI), for difference between groups: -7, 6 l min(-1)). There was a comparable improvement in secondary efficacy variables, including clinic lung function measurements, in the two treatment groups. The incidence and type of most adverse events were similar in the two treatment groups. There was no difference in the adjusted geometric mean morning serum cortisol levels after treatment with the HFA 134a and CFC pMDI. Therefore, the fluticasone propionate HFA 134a pMDI constitutes a suitable replacement for the established CFC pMDI at a microgram equivalent dose.

Safety of hydrofluoroalkane-134a beclomethasone dipropionate extrafine aerosol.

Herein we assess the safety of an inhaled formulation of beclomethasone dipropionate (BDP) which uses the propellant hydrofluoroalkane-134a (HFA) for the treatment of asthma. Acute local tolerability (as assessed by the incidence of cough and mean forced expiratory volume after 1 s inhalation) was similar for both BDP and placebo formulated in either chlorofluorocarbon (CFC) or HFA propellants. A total of 43 patients were treated with HFA-BDP (0, 200, 400 or 800 micrograms day-1) or CFC-BDP (800 micrograms day-1) for 14 days and their 24 h urinary free cortisol (UFC) excretion and response to cosyntropin stimulation were measured. There was no difference in UFC between any of the doses of HFA-BDP and CFC-BDP. Adrenal responsiveness to cosyntropin stimulation was normal in all but one patient. Two large 12 week phase III trials compared HFA-placebo, HFA-BDP 400 micrograms day-1 and CFC-BDP 800 micrograms day-1 (n = 347), and HFA-BDP 800 micrograms day-1 and CFC-BDP 1500 micrograms day-1 (n = 233). For HFA-BDP at either dose, CFC-BDP 800 micrograms day-1 and HFA-placebo, the number of patients with morning plasma cortisol concentrations below normal was less than 4.4% but was 14.6% for CFC-BDP 1500 micrograms day-1. The incidence of adverse events was lower in the HFA-BDP groups than in the CFC-BDP groups (P = 0.012). The data indicate that, at doses of up to 800 micrograms day-1, HFA-BDP is at least as well tolerated as CFC-BDP. Other studies have found that equivalent efficacy is reached at lower doses of HFA-BDP than CFC-BDP. Equivalent efficacy at a lower dose and equivalent safety at the same dose imply that HFA-BDP may have a more favourable risk: benefit ratio than CFC-BDP when used at the recommended lower doses.