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Key issues in inhalation therapy in children.

In order to achieve asthma control it is essential that children receive the appropriate education and training pertaining to the management of their disease, are prescribed the correct medication according to severity, and most importantly, are prescribed the correct inhaler to ensure medication is deposited in their lungs. There are three major misconceptions which physicians and patients have regarding the use of inhalers in children. Firstly, that the nebulizer is more effective than a pressurised metered dose inhaler (pMDI) plus spacer in treating acute asthma in children. Secondly that using an inhaler correctly is easy, and lastly that correct use of the inhaler, once taught, persists over time. However, recent studies have shown that these conceptions are false. Firstly, comparable efficacy is achieved by treatment with inhaled corticosteroids or bronchodilators delivered through a nebulizer and a pMDI plus spacer, both when used to treat acute asthma and for maintenance therapy. Secondly, contrary to general opinion, using an inhaler correctly is difficult for children. Many children with asthma use their inhaler devices incorrectly, even after instruction for correct use of the inhaler. Thirdly, correct inhalation technique deteriorates over time; and inhalation instructions, therefore, should be given repeatedly to achieve and maintain correct inhalation technique in asthmatic children. The profile of the ideal inhaler comprises good drug deposition in the lower airways, deliverance of a consistent dose, being easy to teach and to use correctly, and being small in size and convenient to handle. It should also be multidose, require a low inspiratory airflow for activation, provide feedback to patients on correct use of the inhaler, be re-usable, have an appealing design and feel, and have a reliable dose counter which may help to monitor the patient's compliance. The Novolizer device, a new multidose dry powder inhaler (DPI), shows many of these characteristics making it potentially very suitable for children with asthma.

Administration, Inhalation↗

Rationale for the choice of an aerosol delivery system.

The choice of an aerosol delivery system depends on numerous factors such as the drug itself, the characteristics of the aerosol generator, the patient and his or her disease, the physician, and the clinical setting, notably an emergency situation or not. Some rules always apply: an ultrasonic nebulizer should not be used to aerosolize a drug suspension; whenever possible, the same type of aerosol generator should be used for all inhaled medications received by a given patient; for outpatients, education is a major factor to ensure treatment efficacy. When the deposition of the aerosolized drug is aimed at the terminal respiratory units, nebulizers that generate micronic aerosols should be chosen. When the deposition of the aerosolized drug is aimed at the conducting airways, the metered dose inhaler (MDI) is the first choice. However, the MDI is often ill-used, notably in children and elderly people. Therefore, other inhalation devices have been developed: spacers, dry-powder inhalers, breath-actuated MDIs and, more recently, piezo-electric devices. They have been shown to increase lung deposition of drugs in poor coordinators but they all have limitations, which may affect their clinical efficacy. These limitations include the cumbersome dimensions of spacers, the dependency of lung deposition of dry powders on the inspiratory flow rate, the need for reformulation of breath-actuated or not MDIs with CFC-free gases. Nebulization of drugs should be considered only when no portable device is available for the considered drug, or in case of failure of other forms of aerosol administration.

Aerosols↗

[Investigation of the effects of puff times and spacer devices on the distribution pattern of a Becotide 100 inhaler in the twin impinger].

In order to investigate the dispersion pattern and compare the effect of spacer devices (Volumatic, Volumatic Soft and InspirEase), the Becotide 100 inhaler actuating 100 micrograms of beclomethasone dipropionate (BDP) per shot was studied with respect to its distribution ratio in a twin impinger and also compared with that of the Becotide 50 inhaler. The distribution patterns of BDP during each stage of the twin impinger were not affected by the puff times of the Becotide 100 inhaler. No significant difference was observed when the distribution ratios between the Becotide 50 inhaler and Becotide 100 inhaler were compared. All of these three spacer devices reduced the deposition ratio in stage I which is assumed to be the oral cavity and oropharynx. As the puff times of the Becotide 100 inhaler increased, the BDP deposited in the spacer increased and that of stage II assumed to be the lung decreased. These results suggested that the inhalation volume of BDP would depend on the puff times during clinical use and the inhalation volume of BDP for the Becotide 100 inhaler would be double that of the Becotide 50 inhaler. The spacer devices could decrease the local adverse effects caused by deposited BDP in the oral cavity. When using large spacer devices, one or two puff times into the spacer would be recommended for the best clinical effectiveness. The Volumatic could be expected to produce a superior BDP inhalation volume by reducing the deposition in the oral cavity in the 3 spacer devices examined in this study.

Beclomethasone↗

[Different inhaler devices in acute asthma attacks: a randomized, double-blind, placebo-controlled study].

OBJECTIVE: To verify the efficacy, side effects, and cost of treatment of acute asthma attacks, using different inhaler devices. METHODS: This is a randomized, double-blind, placebo-controlled study. Salbutamol was administered via a nebulizer, a metered-dose inhaler (attached to a commercially available spacer device), a homemade non-valved spacer device, or a dry powder inhaler. Assessments were made at zero, 20, 40 and 60 minutes, followed by the application of salbutamol and placebo with another device. Forty children (mean age of 11+/-3.5 years) with acute asthma attacks, were evaluated. Clinical score, forced expiratory volume in one second and side effects were analyzed. The costs for medication and spacer devices were calculated. RESULTS: There is no difference between groups regarding clinical score and variation of forced expiratory volume in one second. There was a major variation in the heart rate response to the nebulizer (35%) compared to the commercially available spacer and dry powder inhaler (15 and 17%) and between the homemade spacer and the commercially available spacer (28 and 15%) (p = 0.004). The nebulizer and homemade spacer caused more tremor (p = 0.02). The cost of treatment was higher for the nebulizer and commercially available spacer (p = 0.0001). CONCLUSIONS: The nebulizer was more expensive and used more medicine, showing the same efficiency. The homemade spacer was cheaper, but presented more side effects. The commercially available spacer was as expensive as the nebulizer, although safer. The dry powder inhaler was cheaper, but, just as the homemade spacer, it also caused tachycardia.

Acute Disease↗

Pressurised aerosol deposition in the human lung with and without an "open" spacer device.

A radiotracer technique has been used to assess aerosol delivery from a pressurised metered dose inhaler, used both with and without a 10 cm cylindrical spacer attachment (Syncroner), which has an open section in its upper surface. The radionuclide technetium-99m (99mTc) was added to sodium cromoglycate in a canister (Intal inhaler; 1 mg/puff); in vitro studies with a multistage liquid impinger showed that the radiolabel acted as a marker for the presence of drug over a wide range of particle sizes. Ten healthy volunteers were studied after they had inhaled from (1) a metered dose inhaler alone (slow inhaled flow rate, about 25 l/min); (2) metered dose inhaler plus spacer (slow flow rate); and (3) metered dose inhaler plus spacer (fast inhaled flow rate, about 100 l/min). Inhalation was coordinated with firing the spray and was followed by 10 seconds' breath holding. With the metered dose inhaler alone a mean 11.0% (SEM 1.4%) of the dose reached the lungs, compared with significantly higher doses for slow (16.1% (2.2%] and fast (13.3% (1.7%] inhalations through the spacer. The distribution pattern within the lungs was significantly more peripheral after slow inhalation. Oropharyngeal deposition was halved by the spacer. The open spacer should teach patients good coordination and delivers more aerosol to the lungs than a correctly used metered dose inhaler.

Adolescent↗

Proper use of aerosol corticosteroids to control asthma.

Aerosol glucocorticoids are highly effective in the treatment of bronchial asthma. Clinically apparent systemic hypercortisolism is virtually nonexistent in patients who receive such therapy, although local effects of candidiasis or dysphonia may occur. Treatment failures can often be attributed to poor patient compliance or incorrect use of the pressurized aerosol inhaler. The addition of a spacer device to the inhaler improves the technique and the results in many patients. Furthermore, many patients with asthma require 2 or 3 times the conventional dose of aerosol corticosteroids for optimal control of pulmonary function. Careful coaching is essential for the successful use of aerosol corticosteroids.

Administration, Inhalation↗

[Endobronchial bronchodilators].

There are two families of inhaled bronchodilators: beta-2-mimetics and vagolytics. They are equally effective in patients with chronic obstructive pulmonary disease (COPD), whereas beta-mimetics are usually superior in asthmatics. The clinical benefits linked to long acting beta-mimetics like salmeterol are already established in asthmatics. Metered dose aerosols remain the most widely used type of inhaler, eventually connected to a spacer, together with powder inhalers. Usual bronchodilators are now prescribed on demand rather than on a regular basis. There is no proof that beta-mimetics are casually related to asthma deaths. Inhaled corticosteroids, which have no acute bronchospasmolytic properties, are the first-choice chronic drug treatment of moderate to severe asthma; they are currently being evaluated in COPD.

Administration, Inhalation↗

Delivery of salbutamol pressurized metered-dose inhaler administered via small-volume spacer devices in intubated, spontaneously breathing rabbits.

Little is known about the ability of small-volume valved spacer devices to deliver a significant amount of an aerosolized drug to the lungs of babies. This study compared the in vitro delivery of salbutamol administered via Aerochamber-Infant (145 mL), Babyhaler (350 mL), and metallic NES-spacer (250 mL), as well as the in vivo delivery using an animal model. The lung deposition study of technetium-99m-labeled salbutamol was conducted in six anesthetized, intubated (3.0-mm endotracheal tube simulating oropharyngeal deposition), spontaneously breathing New Zealand White rabbits, a model for 3-kg babies. Each rabbit was studied on three separate occasions, once with each spacer device. The amount of radioactivity deposited in the spacer device, the endotracheal tube, the lungs, or the body was measured by a gamma camera and expressed as a percentage of the emitted labeled dose. The emitted dose and particle size distribution of salbutamol via the three spacer devices were measured using unit dose sampling tubes and an eight-stage Anderson cascade impactor, respectively. The results were compared by ANOVA or Student-Newman-Keuls test when indicated. In vitro, the NES-spacer and Babyhaler were equivalent for delivering particles <5.8 microm in diameter (NES-spacer = Babyhaler > Aerochamber-Infant; p < 0.05). In vivo, the lung and body deposition was low with all spacer devices (range: 0.52-5.40% of the delivered dose) but greater with the NES-spacer than with the Aerochamber-Infant or the Babyhaler (5.40 +/- 2.40%, 2.91 +/- 0.86%, 0.52 +/- 0.46%, respectively; p = 0.002). These results suggest the metal-valved spacer device may be preferable for delivering pressurized aerosols to spontaneously breathing infants.

Administration, Inhalation↗

Improvement of pressurised aerosol deposition with Nebuhaler spacer device.

The effect on aerosol deposition from a pressurised metered dose inhaler of a 750 cm3 spacer device with a one way inhalation valve (Nebuhaler, Astra Pharmaceuticals) was assessed by means of an in vivo radiotracer technique. Nine patients with obstructive lung disease took part in the study. The pattern of deposition associated with use of a metered dose inhaler alone was compared with that achieved with the spacer used both for inhalation of single puffs of aerosol and for inhalation of four puffs actuated in rapid succession and then inhaled simultaneously. On each occasion there was a delay of 1 s between aerosol release and inhalation, simulating poor inhaler technique. With the metered dose inhaler alone, a mean (SEM) 8.7 (1.8)% of the dose reached the lungs and 80.9 (1.9)% was deposited in the oropharynx. With single puffs from the spacer 20.9 (1.6)% of the dose (p less than 0.01) reached the lungs, only 16.5 (2.3)% (p less than 0.01) was deposited in the oropharynx, and 55.8 (3.1)% was retained within the spacer itself. With four puffs from the spacer 15.2 (1.5)% reached the lungs (p = 0.02 compared with the metered dose inhaler alone, p less than 0.01 compared with single puffs from the spacer), 11.4 (1.2)% was deposited in the oropharynx, and 67.5 (1.8)% in the device itself. It is concluded that the spacer device gives lung deposition of metered dose aerosols comparable to or greater than a correctly used inhaler and oropharyngeal deposition is greatly reduced. The spacer should be used preferably for the inhalation of single puffs of aerosol but may also be used for the inhalation of up to four puffs actuated in rapid succession and then inhaled simultaneously.

Adult↗

Beclomethasone dipropionate and salbutamol by metered dose inhaler in infants and small children with recurrent wheezing.

The efficacy of beclomethasone dipropionate (BDP) to control respiratory symptoms was evaluated in 31 children under age 2 years with recurrent wheezing. The study was conducted in a double-blind, parallel, and placebo-controlled fashion. The two study groups received either salbutamol plus BDP 200 microg bid by metered dose inhaler (MDI) with a spacer, or salbutamol MDI plus a placebo. Inhaled corticosteroid (IC) and placebo were administered for 8 weeks. Patients were seen every 2 weeks as outpatients, and their progress was evaluated by clinical examination and a daily symptom score card. At the end of the study, patients in both groups had significantly decreased symptoms. No significant difference was found between BDP and placebo groups regarding clinical score, number of salbutamol doses, sleep disturbances, number of symptom-free days, feelings of insecurity of mothers regarding the infants' life due to wheezing, and mothers' perceptions of progress in their infants' respiratory symptoms. We conclude that salbutamol plus 200 microg bid of BDP inhaled from an MDI with a spacer for 8 weeks is no better than salbutamol alone for decreasing recurrent wheezing in small children under age 24 months.

Administration, Inhalation↗

Improvement in sodium cromoglycate delivery from a spacer device by use of an antistatic lining, immediate inhalation, and avoiding multiple actuations of drug.

BACKGROUND: Aerosols generated from metered dose inhalers may be highly charged. The aim of this study was to determine whether lining the walls of a polycarbonate spacer device with an antistatic agent would result in an increase in drug output. The effects of multiple actuations of drug into the spacer device and increasing residence time of drug within the spacer were also determined. METHODS: The amount of sodium cromoglycate contained in particles of various size available for inhalation (per 5 mg actuation) from a 750 ml polycarbonate spacer was determined by impinger measurement and spectrophotometric assay. RESULTS: Lining the spacer with an antistatic agent increased the mean (SD) amount of sodium cromoglycate in particles < 5 microns available for inhalation (per 5 mg actuation) by 244% from (0.59 (0.03) to 1.44 (0.2) mg). When there was a 20 second interval between actuation into the spacer device and inhalation, sodium cromoglycate available for inhalation in particles < 5 micrograms decreased by 67% (from 0.59 (0.03) mg to 0.2 (0.01) mg). Use of the spacer device increased sodium cromoglycate available for inhalation in respirable particles (< 5 microns) by 18% compared with direct delivery by metered dose inhaler. Multiple actuations into the spacer decreased the amount of sodium cromoglycate available for inhalation in particles < 5 microns by 31% after two actuations and 56% after three acutations. CONCLUSIONS: Multiple actuations of sodium cromoglycate into a spacer device before inhalation should be avoided, and inhalation from spacer devices should take place immediately after actuation to ensure maximum dose. Lining of a standard spacer device with an antistatic agent significantly increased output of sodium cromoglycate. This may have implications for improved therapeutic response and drug cost.

Administration, Inhalation↗

Holding chambers (spacers) versus nebulisers for beta-agonist treatment of acute asthma.

BACKGROUND: In acute asthma inhaled beta2-agonists are often administered to relieve bronchospasm by wet nebulisation, but some have argued that metered-dose inhalers with a holding chamber (spacer) can be equally effective. Nebulisers require a power source and need regular maintenance, and are more expensive in the community setting. OBJECTIVES: To assess the effects of holding chambers (spacers) compared to nebulisers for the delivery of beta2-agonists for acute asthma. SEARCH STRATEGY: We last searched the Cochrane Airways Group trials register in January 2006 and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2005). SELECTION CRITERIA: Randomised trials in adults and children (from two years of age) with asthma, where spacer beta2-agonist delivery was compared with wet nebulisation. DATA COLLECTION AND ANALYSIS: Two reviewers independently applied study inclusion criteria (one reviewer for the first version of the review), extracted the data and assessed trial quality. Missing data were obtained from the authors or estimated. Results are reported with 95% confidence intervals (CI). MAIN RESULTS: This review has been updated in January 2006 and four new trials have been added. 2066 children and 614 adults are now included in 25 trials from emergency room and community settings. In addition, six trials on in-patients with acute asthma (213 children and 28 adults) have been reviewed. Method of delivery of beta2-agonist did not appear to affect hospital admission rates. In adults, the relative risk of admission for spacer versus nebuliser was 0.97 (95% CI 0.63 to 1.49). The relative risk for children was 0.65 (95% CI: 0.4 to 1.06). In children, length of stay in the emergency department was significantly shorter when the spacer was used, with a mean difference of -0.47 hours (95% CI: -0.58 to -0.37). Length of stay in the emergency department for adults was similar for the two delivery methods. Peak flow and forced expiratory volume were also similar for the two delivery methods. Pulse rate was lower for spacer in children, mean difference -7.6% baseline (95% CI: -9.9 to -5.3% baseline). AUTHORS' CONCLUSIONS: Metered-dose inhalers with spacer produced outcomes that were at least equivalent to nebuliser delivery. Spacers may have some advantages compared to nebulisers for children with acute asthma.

Acute Disease↗

Comparison of the bronchodilating efficacies of a novel salbutamol metered dose powder inhaler and a pressurised metered dose aerosol with a spacer.

In a two-day, randomised, double-blind, double-dummy, cross-over multicenter study, the bronchodilating effect of 100 micrograms of salbutamol (CAS 18559-94-9) inhaled from a new metered dose powder inhaler (MDPI; Taifun) was compared with that of an identical dose of salbutamol inhaled from a conventional pressurised metered dose inhaler connected to a spacer (pMDI + S). Thirty-six non-smoking, adult asthmatic outpatients with a baseline forced expiratory volume in 1 s (FEV1) between 35 and 70% of the predicted value participated in the study. After inhalation of the study medication pulmonary function, FEV1 and airway resistance (R(aw)), blood pressure (BP), and heart rate (HR) were measured up to 6 h. Area under the FEV1 vs. time curve (AUCFEV1) was used as the primary efficacy parameter, and the 90% confidence intervals (CI) were used to judge clinical equivalence. Other efficacy parameters were used in supportive analyses as secondary parameters. Both treatments produced a clear improvement in pulmonary function. The mean +/- SD AUCFEV1 were 893 +/- 281 and 889 +/- 2761.min after MDPI and pMDI + S, respectively. The 90% CI for the relative efficacy of the MDPI is from 98 to 103% of that of the pMDI + S. Also the other efficacy parameters gave similar results without significant differences: the mean +/- SD values of percent increase in FEV1 were 47.2 +/- 19.3 and 44.7 +/- 20.8, the maximum absolute value of FEV1 were 2.87 +/- 0.77 and 2.86 +/- 0.77, the maximum percent decrease in R(aw) 53.2 +/- 20.5 and 55.0 +/- 19.1, and the minimum absolute value of R(aw) 0.27 +/- 0.11 and 0.30 +/- 0.12 kPa.s.l-1 for the MDPI and pMDI + S, respectively. The salbutamol doses had no significant effect on BP or HR, and were equally well tolerated. Furthermore, 57.5% of the patients preferred the MDPI, 35% the pMDI + S, and 7.5% considered that there was no difference between the devices. In conclusion, this study demonstrates that the new MDPI is as effective and safe a device as a conventional pMDI connected to a spacer in administering inhaled salbutamol for asthmatic patients. Further, most patients considered the MDPI easier to handle, and preferred it over the pMDI + S.

Adult↗

A randomised controlled trial to assess the relative benefits of large volume spacers and nebulisers to treat acute asthma in hospital.

OBJECTIVES: To compare the clinical effectiveness, acceptability, and cost benefit of administering beta2 agonists by means of a metered dose inhaler and large volume spacer with conventional nebulisers to children admitted to hospital with acute asthma. METHODS: A randomised controlled trial was conducted over five months. Sixty one children older than 3 years admitted to a large teaching hospital and a district general hospital with acute asthma completed the study. Children received either 5 mg of salbutamol up to one hourly by jet nebuliser, or up to 10 puffs of salbutamol 100 microg by means of a metered dose inhaler and spacer up to one hourly. RESULTS: Median hospital stay was 40 hours in the nebuliser group and 36.5 hours in the spacer group. Asthma disability scores at two weeks after discharge were significantly improved in the spacer group. Drug costs were pound 14.62 less for each patient in the spacer group. CONCLUSIONS: Large volume spacers are an acceptable, cost effective alternative to nebulisers in treating children admitted with acute asthma, provided that the children can use the mouthpiece, and symptoms are not severe. Their use facilitates effective home treatment by parents, with subsequent reduction in morbidity and re-admission rates.

Acute Disease↗

[Inhalation chambers: an alternative to the conventional inhalator?].

BACKGROUND: Aerosol inhalers constitute the most commonly used form of administration of medication by most of the patients with respiratory disease although incorrect usage is a demonstrated fact in many studies. A previous study demonstrated that, despite correct instruction by health care staff and the patients, 30% of the same use these inhalers incorrectly. In the present study, the efficacy of inhalation chambers (750 ml) and spacers (50 ml) versus the conventional inhaler was evaluated by quantification of bronchodilator response. METHODS: Fifty-six stable patients with chronic obstruction to air flow in habitual treatment with aerosol inhalers (AI) were studied. For this study 27 patients used the chamber and 29 the spacer. The patients using the maneuvers correctly (n = 42) and those that did not (n = 14) were studied together and separately. RESULTS: Patients using the inhaler incorrectly were found to benefit significantly from either of the procedures. Upon comparison of the chambers (750 ml) with the spacers (50 ml) a significant improvement was observed with the former. CONCLUSIONS: The response to bronchodilator treatment in patients not using aerosol inhalers correctly improves significantly upon use of either inhalation chambers or spacers with the former demonstrating the best results.

Adult↗

[Effect of salbutamol administered directly by a nebulizer or by means of a spacer on bronchodilation].

During three successive days in 14 patients with bronchial asthma after application of Salbutamol directly from the metered-dose inhaler (MDI) or indirectly by spacer the changes of FEF and FEV1 were measured. For inhalation through spacer the double blind crossover trial with placebo was used. Out of 12 patients three of them responded with better flows (FEV1, FEF) after inhalation via MDI. In 7 of them there were no significant differences between ways of application while in two of them the flows by spacer were significantly better. Tachypnea, low lung volumes as well as poor co-operation of the patient, especially elderly, should speak in favour of the use of spacer. However, in young, co-operative asthmatic patients the MDI is suitable. Further controlled studies of new applications of inhalation therapy should be studied.

Adult↗

Home-made spacers for bronchodilator therapy in children with acute asthma: a randomised trial.

BACKGROUND: A metered-dose inhaler (MDI) with spacer is the best way to deliver bronchodilator therapy for treatment of acute asthma. In developing countries, commercially produced spacers are generally unavailable or too costly. We tested the efficacy of home-made spacers (500 mL plastic bottle, polystyrene cup) compared with a conventional spacer for delivery of a beta2 agonist via MDI for children with acute asthma. METHODS: We studied children aged 5 to 13 years with acute asthma, stratified into those with mild airways obstruction (peak expiratory flow [PEF] 60-79% of predicted value) or moderate to severe airways obstruction (PEF 20-59% of predicted value). A beta2 agonist (fenoterol hydrobromide) was given via MDI and one of four randomly assigned spacers (conventional spacer, sealed 500 mL plastic bottle, unsealed 500 mL bottle, 200 mL polystyrene cup). Clinical score, pulmonary function tests, and oximetry were recorded at baseline and 15 min after treatment. If a second bronchodilator treatment was needed, nebulised fenoterol was given and the assessment repeated 15 min later. Primary outcome measures were changes in clinical score and pulmonary function, and need for and response to nebulisation. FINDINGS: 88 children were eligible for study. In 44 children with moderate to severe airways obstruction, a cup gave significantly less bronchodilation (median increase in: forced expiratory volume in 1 s [FEV1] 0%; PEF 12%) compared with the conventional spacer (37%; 59%), sealed bottle (33%; 36%), or unsealed bottle (18%; 21%, p<0.05 for difference between groups). Nebulisation was required by ten of 11 who had used a cup, nine of 11 who had used an unsealed bottle, eight of 11 who had used a sealed bottle, and only four of 11 who had used a conventional spacer. After nebulisation, improvement in FEV1 (15.5%) and PEF (26%) was more marked in children who had used a cup than in those who had used a conventional spacer (5.5% FEV1; 4% PEF), sealed bottle (3%; 0%), or unsealed bottle (7%; 9%). For 44 children with mild airways obstruction, response to bronchodilator was similar for all spacers and need for nebulisation was not associated with use of a particular spacer. INTERPRETATION: A conventional spacer and sealed 500 mL plastic bottle produced similar bronchodilation, an unsealed bottle gave intermediate improvement in lung function, and a polystyrene cup was least effective as a spacer for children with moderate to severe airways obstruction. Use of bottle spacers should be incorporated into guidelines for asthma management in developing countries.

Administration, Inhalation↗

Systemic bioavailability and potency of high-dose inhaled corticosteroids: a comparison of four inhaler devices and three drugs in healthy adult volunteers.

OBJECTIVES: To compare the systemic bioavailability (assessed by cortisol suppression) of high-dose budesonide when given by four inhaler devices and orally. Also studied are the relative systemic potencies of three inhaled steroids (budesonide, fluticasone propionate, and beclomethasone dipropionate) when given by metered-dose inhaler (MDI) with a large volume spacer. DESIGN: Double-blind, crossover, placebo-controlled trial. PARTICIPANTS: Sixteen healthy, steroid-naive adult volunteers. METHODS: On separate occasions, each subjects took 4 mg of budesonide through the following devices: MDI alone, MDI with 750-mL. spacer, dry-powder inhaler and nebulizer; 4 mg of budesonide was also taken orally to assess the effects of GI absorption. For the drug comparison, each subject took 4 mg of budesonide, fluticasone, and beclomethasone, and 2 mg of budesonide and fluticasone by MDI and spacer. RESULTS: Greatest percent suppression (95% confidence interval) of 9:00 AM cortisol with budesonide was observed with MDI alone (73% [57 to 90]) and turbohaler (72% [58 to 86]) compared with MDI spacer (42% [22 to 64]) and oral administration (14% [+6- to -34]). Nebulized budesonide produced an insignificant rise in 9:00 AM cortisol level. The most suppressive drug (given by MDI spacer) was fluticasone at 4 mg (86% [82 to 91]) and at 2 mg (72% [59 to 85]). The least suppressive drug was budesonide at 4 mg (43% [22 to 64]) and at 2 mg (25% [3 to 47]). The effects of 4 mg of beclomethasone were intermediate (66% [49 to 82%]). CONCLUSIONS: The choice of delivery device for administration of budesonide can lead to important differences in systemic bioavailability. Fluticasone has greater systemic potency than budesonide or beclomethasone when given at microgram equivalent dosage. The systemic potency ratio of fluticasone propionate to budesonide in normal human volunteers in the present study is similar to the therapeutic potency ratio of the drug in asthmatic patients (approximately 2:1).

Administration, Oral↗