Inhalation, administration asthma medications

Direct airway administration of asthma medications through inhalation is the most efficient route and minimizes systemic adverse effects. 

Direct airway administration of asthma medications through inhalation is most efficient and minimizes systemic adverse effects. Poor inhaler technique can result in increased oropharyngeal deposition of the drug with decreased efficacy and increased adverse effects. Figure 11-1 provides... 

One of the most convincing demonstrations of the effect of placebos on asthma was conducted by a research team led by Thomas Luparello, a psychiatrist at the State University of New York.41 Luparello s team asked 40 asthmatic patients to inhale what they presented as irritants or allergens previously identified by the subjects as triggers for their asthmatic attacks. In fact, the substance they inhaled was an inert saline solution - simple table salt dissolved in water. Nineteen of the 40 asthmatic patients reacted with a significant increase in airway resistance, and 12 of them developed full-blown bronchospasm attacks. These asthma attacks were then reversed by the administration of a placebo presented as an asthma medication. 

Pulmonary delivery of drugs is the administration route of choice in respiratory diseases such as chronic obstructive pulmonary disease and asthma. Different devices are available, including metered-dose inhalers, dry powder inhalers, and nebulizers, and nearly 80% of asthmatic patients worldwide use metered dose inhalers (1). Chlorofluorocarbons have been used as an aerosol propellant in metered-dose inhalers however, they deplete the ozone layer and are being replaced by more environment-friendly propellants, even though the contribution of aerosols of this type to the total global burden of chlorofluorocarbons is less than 0.5%. The first chloro-fluorocarbon-free metered-dose inhaler for asthma treatment was approved by the FDA in 1996 (2) and the European Union has set 2005 as a target date for the withdrawal of all chlorofluorocarbon-based inhalers (1). In the USA, prescriptions for chlorofluorocarbon-free medications rose from 16.4 million in 1996 to 33.8 million in 2000 (2). Most of the chlorofluorocarbon-free medications were steroids for nasal use (27.2 million). However, chlorofluorocarbon-containing medications stiU represented two-thirds of all prescriptions and increased from 63.0 to 67.6 million dispensed (2). 

An inhalable medication that relaxes the muscles in the airways (bron-chodilator) is frequently administered when airways obstruction is identified. In this bronchodilator trial test, the spirometry test is subsequently repeated and compared to the results from the initial spirometry test. If there is substantial improvement in lung function with the administration of the bronchodilator, the airways obstruction is reversible. An example of a lung disease with reversible airways obstruction is asthma, in which s)nnptoms occur episodically when airways obstruction occurs. If there is little or no improvement after the administration of the bronchodilator, the airways obstruction is fixed. An example of a limg disease with fixed airways obstruction is BO, where there is scarring of the airways. 

In the mid-1950s the first pressurized metered dose inhaler (MDI) was developed for the administration of bronchodilator drugs locally to the lung. It was a major advance for the treatment of asthma since it made aerosol medications readily available in an inexpensive small multidose device. 

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