Effect of a timed interval between inhalation of beta-agonist and corticosteroid aerosols on the control of chronic asthma

A comparison of the bronchodilator effect of salbutamol inhaled via Turbuhaler as two consecutive doses or as two divided doses at different time intervals

The aim of the study was to compare the bronchodilatory effect of 2x50 microg salbutamol inhaled via Turbuhaler(R) as two consecutive doses compared with two divided doses (50+50 microg) at different time intervals. The study was of a randomized, double-blind, crossover design. The patients inhaled two doses of 50 microg salbutamol immediately after each other and with a time interval between the doses of 1.5, 3, 5, or 10 mins. Forced expiratory volume in 1 s (FEV(1)) was measured before the first inhalation and at 1, 2. 5, 4.5, 9.5, 15, 20, 30, and 60 min after the first inhalation. Seventeen asthmatic patients (8 men) with a mean age of 32 years (range: 19-49 years), mean FEV(1) of 2.9 l (range: 1.7-3.9 l) and a mean FEV(1) in percentage of predicted normal value of 77% (range: 63-91%) participated. The mean reversibility 15 min after inhaling 100 microg salbutamol from pMDI was 23% (range: 16-35%). The mean maximum increase in FEV(1) from baseline ranged between 18.6% (consecutive doses) and 21.2% (1.5 min between doses), corresponding to a difference between the treatments of 0.06 l. There were no significant differences in maximum FEV(1) or time to reach maximum FEV(1) between the treatments. We were not able to show any clinically relevant differences in maximal bronchodilating effect, assessed as FEV(1), in stable asthmatics, when therapeutic doses of salbutamol were given via Turbuhaler either as two consecutive doses or as two divided doses separated by different time intervals.

Pharmacist knowledge and ability to use inhaled medication delivery systems

Previous studies have shown that a significant proportion of patients and physicians have difficulty using metered dose inhaler (MDI) delivery systems. It has been suggested that paramedical personnel such as pharmacists could address this problem by serving as patient educators. Few studies have assessed a pharmacist's knowledge of and ability to use inhaled devices, including not only the conventional MDI but newer devices such as an add-on spacing chamber (Aerochamber) and a multidose dry powder inhaler (Turbuhaler). We therefore approached all pharmacists in a predefined geographic area of a large city in order to evaluate their knowledge of and ability to use inhaled medications. Of 62 pharmacists approached, 45 (73 percent) agreed to participate. Ability to use the conventional MDI, Aerochamber (A), and Turbuhaler (T) was graded by a trained observer using a checklist of 11 essential steps. The percentage of pharmacists performing greater than 6, 8, and 10 steps correctly for each device was MDI = 96 percent, 87 percent, 62 percent; MDI + A = 80 percent, 76 percent, 47 percent; T = 67 percent, 64 percent, 29 percent. The most common problems with the MDI were forgetting to shake prior to use and coordinating inspiration with actuation. The most common problems with the MDI + A were forgetting to shake prior to use, remembering to inspire after actuation, and breath holding after inspiration. The most common difficulty with the T was total unfamiliarity with the device with 33 percent of pharmacists achieving less than 2 steps correctly. The observer subsequently administered a questionnaire of 11 clinically relevant questions for each of the devices tested. The mean score was 50 percent with only 21 percent of pharmacists scoring above 70 percent. Thirty-three percent of respondents had no instruction in device use beyond reading the packing insert; 40 percent had received instruction from a pharmaceutical representative; only 24 percent had received instructions from professional school. We conclude that a pharmacist's knowledge of inhaling devices is roughly proportional to the length of time the device has been available and that pharmacists form another group of health care professionals who require further teaching regarding inhaled medication delivery systems.

Optimizing drug delivery from metered-dose inhalers

Metered-dose inhalers (MDIs) are being used with increasing frequency to administer medication used in the treatment of respiratory tract disorders. Inhaled medication is delivered directly to the tracheobronchial tree, allowing for a rapid and predictable onset of action. Studies show that only about ten percent of the dose from an MDI actually reaches the lung. The site of deposition within the lung is influenced by the aerosol characteristics, interpatient variability, and the technique by which the patient uses the inhaler. Spacer devices have been designed to overcome some of the problems encountered with MDIs and may be beneficial in certain groups of patients. The studies reviewed in this article suggest ways to alter the variables affecting inhalation in order to optimize drug delivery so that the patient will obtain the most benefit from the inhaled medication.

Beclomethasone dipropionate. A reappraisal of its pharmacodynamic properties and therapeutic efficacy after a decade of use in asthma and rhinitis

Inhaled beclomethasone dipropionate is now well established in the management of asthma. Studies conducted over the last decade, and since the drug was previously reviewed in the Journal, have confirmed that inhaled beclomethasone dipropionate 400 to 800 micrograms daily can reduce the need for oral maintenance corticosteroids in the majority of asthmatic patients requiring such therapy, and that increasing the dosage to 2000 micrograms daily may provide additional clinical benefit in some patients unresponsive to usual therapeutic dosages. Follow-up over a period of several years has confirmed that the initial response to inhaled beclomethasone can be maintained in most patients. Recent studies indicate that beclomethasone dipropionate 400 micrograms daily is equally effective when administered in 2 or 4 divided doses in patients with stable asthma, but it is likely that the lower frequency of administration will be less effective when the asthma is unstable. Recent studies have established the usefulness and good tolerability of intranasal beclomethasone dipropionate in the treatment of perennial and seasonal rhinitis, where the drug has been shown to be more effective than intranasal sodium cromoglycate and similar in efficacy to flunisolide. Nasal polyps decrease in size during continuous treatment with intranasal beclomethasone dipropionate, but enlarge again during periods of respiratory infection. After a decade of treatment with inhaled and intranasal beclomethasone dipropionate, there is no evidence that the drug damages the tracheobronchial lining or the nasal mucosa. Thus, the initial promise of beclomethasone dipropionate has been fulfilled. It has had an important role in asthma therapy over the past decade, which will continue into the future.