Bronchodilator trial

Bronchodilator trial When a spirometry test Reversible airways... 

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. 

Bronchodilator trial Airways Airways obstruction may Airways Airways... 

Cromakalim. Cromakalim has along half-life (254). Cromakalim at an oral dose of 1.5 mg ia humans significantly lowers blood pressure 19/12 mm Hg (systohc/diastoHc pressure). It iacreases reaal blood flow, PRA, and heart rate. Cromakalim has bronchodilating activity that is beneficial for hypertensive asthmatic patients. Because of some undesirable effects seen ia cardiac papillary muscles of animals oa long-term treatmeat, future clinical trials are to be carried out usiag the active enantiomer, lemakalim (BRL 38227). 

Inhaled steroids (commonly used are beclomethasone, budesonide, triamcinolone, fluticasone, flunisolide) appear to attenuate the inflammatory response, to reduce bronchial hyperreactivity, to decrease exacerbations and to improve health status they may also reduce the risk of myocar dial infar ction, but they do not modify the longterm decline in lung function. Whether- steroids affect mortality remains unclear. Many patients appear to be resistant to steroids and large, long-term trials have shown only limited effectiveness of inhaled corticosteroid ther apy. Certainly, the benefit from steroids is smaller in COPD than in asthma. Topical side-effects of inhaled steroids are oropharyngeal candidiasis and hoarse voice. At the normal doses systemic side-effects of inhaled steroids have not been firmly established. The current recommendation is that the addition of inhaled gluco-coiticosteroids to bronchodilator treatment is appropriate for patients with severe to veiy sever e COPD. 

Clinically, it has been confirmed that the drug is an effective bronchodilator with very little cardiovascular activity it does not appear to increase hypoxaemia [439]. A more detailed study [440], comparing salbutamol with isoprenaline and orciprenaline, demonstrated that 200 jug of salbutamol provided effective bronchodilation for at least three hours without detectable cardiac stimulation. Equivalent bronchodilator doses of isoprenaline and orciprenaline were 1000 /ag and 1500 jUg respectively. The bronchial effects of isoprenaline, though initially intense, waned within one hour and cardiac effects were noted. In this trial little objective difference could be detected between salbutamol and orciprenaline at the dose levels used, though most patients expressed preference for salbutamol. 

Reversibility tests to bronchodilators are recommended at all stages of obstructive airways diseases. They are helpful in differentiating patients with COPD with those of asthma. Many patients with COPD and even those with severe airflow obstruction can demonstrate (partial) reversibility. Patients with a positive bronchodilator response i.e. reversibility are more likely to respond to a trial of oral or inhaled corticosteroids. 

Although a variety of interpretations have been issued, reversibility to bronchodilators is considered to be present when the FEV i increases by 200 ml and 12% of the pre-bronchodilator value. Although in the latest GINA guidelines this issue is no longer addressed, the same criteria have been used for evaluation of the response to corticosteroids. A corticosteroid trial compared spirometric tests before and at the end of oral prednisolone (e.g. 30 mg/d) taken for two weeks or a course of inhaled steroid (e.g. beclomethasone 500 pg twice daily or equivalent) taken for six weeks. A positive response to corticosteroids justified prescription of regular inhaled steroid. Subjective improvement as a single efficacy parameter is not considered to be a satisfactory end point. Objective improvement is seen in 10-20% of patients with COPD. 

When taken regularly (2-4 puffs two to four times daily) by patients with perennial (nonseasonal) asthma, both agents modestly but significantly reduce symptomatic severity and the need for bronchodilator medications. These drugs are neither as potent nor as predictably effective as inhaled corticosteroids. In general, young patients with extrinsic asthma are most likely to respond favorably. At present, the only way of determining whether a patient will respond is by a therapeutic trial for 4 weeks. The addition of nedocromil to a standard dose of an inhaled corticosteroid appears to improve asthma control. 

Uniphyllin Continus 200 mg bd Theophylline normally used after a trial of short and long-acting bronchodilators. Needs plasma levels monitored. Increased risk of low potassium when given with prednisolone and bumetanide. 

Inhaled corticosteroids should be added to long-acting bronchodilators to decrease exacerbation frequency in patients with an FEVi less than or equal to 50% predicted who have had two or more exacerbations requiring treatment with antibiotics or oral corticosteroids in a 12-month period - not effective for all patients (steroid trial). 

Q14 After his recovery from this acute bronchitis, would this patient benefit from a trial of a bronchodilator or steroid inhaler ... 

Q12 It is recommended that a trial of a short-acting beta-2-agonist (/S)-agonist) inhaler be made for a few weeks as some COPD patients do benefit from bronchodilation. Although his doctor has prescribed a bronchodilator previously, it may be useful for Bill to try this again. There should also be a trial of a corticosteroid inhaler, as this diminishes the inflammatory component of COPD. If there is no appreciable benefit after four weeks, the steroid should be discontinued. 

There maybe an inflammatory component in obstructive lung disease, and a trial of corticosteroids and bronchodilators is recommended. 

Zyflo was also found to be effective in chronic asthma, as evidenced by two large placebo-controlled trials (143, 144). Improved FEVl and reduced bronchodilator use were the primary clinical endpoints. Interestingly, Zyflo appeared to be most effective in moderate to severe patients. Additional trials indicated that Zyflo is also steroid sparing (145). 

Although there is no standardization for interpretation of severity of obstruction, most pulmonary laboratories state that an FEVi/FVC ratio of less than 70% of the predicted value is diagnostic for obstruction, and the degree of obstruction then is based on the percent predicted of the FEVi. An FEVi of less than 60% of the predicted value is moderate obstruction, and less than 40% of the predicted value is severe obstruction. In patients with obstruction, a dose of a bronchodilator (e.g., albuterol or isoproterenol) by metered-dose inhaler is given during the initial examination. An increase in the FEVi of more than 12% and greater than 0.2 L suggest an acute bronchodilator response. Because bronchodilator responsiveness is variable over time, the lack of an acute bronchodilator response should not preclude a 6- to 8-week trial of bronchodUators and/or corticosteroids. 

Friedman and colleagnes condncted a post hoc pharmacoeco-nomic evalnation of two mnlticenter, randomized trials comparing the combination of ipratropium and albnterol with both dmgs used as monotherapy. Patients who received a combination of ipratropium and albnterol had lower rates of exacerbations, lower overall treatment costs, and improved cost-effectiveness compared with either drng nsed alone. With the introdnction of new bronchodilator therapies, and with no clearly consistent advantage of one class of agents over another, pharmacoeconomic analyses may be nsefnl for clinicians in determining the most appropriate therapy for their patients. 

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