Archive for September, 2009
Posted by James
Table 2 and Table 3 list age-specific incidence rates of colorectal cancer in California from 1988-1995 for men and women, respectively, of each of four racial and ethnic groups. Age-specific colorectal cancer incidence rates were highest in black men and lowest in Latino women. For most ages between 45-85, the rank of incidence rates was consistent (black men > white men > Asian men > black women > white women > Latino men > Asian women > Latino women).
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Posted by James
INTRODUCTION
Colorectal cancer will be diagnosed in approximately 131,000 Americans this year, and about 55,000 will die of the disease, making this cancer the second leading cause of death from cancer in this country. Colorectal cancer screening allows the detection of asymptomatic cancers that are more amenable to curative therapy and also allows the removal of adenomas that could subsequently develop into invasive cancer. Colorectal screening programs are proven to reduce the mortality from colorectal cancer. Nearly every case of colon cancer could be prevented if every American were to undergo periodic total colonic evaluation starting at a very young age. Such a program is impractical, however, and working groups of the American Cancer Society and others have published colorectal cancer screening guidelines that balance the medical benefits of screening against its costs.
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Posted by James
The various guidelines have defined the role of LABAs as adjunctive, given concurrently with an inhaled corticosteroid, and the combination is now considered preferred therapy for moderate and severe persistent asthma. This is supported by a large body of evidence that adding a LABA to the inhaled corticosteroid in patients poorly controlled on just the inhaled corticosteroid is superior to doubling the dose of the inhaled corticosteroids. These studies have been extensively reviewed elsewhere. Most were of short duration (12-24 weeks) and, while virtually all demonstrated greater improvements in symptom control and lung function with combination therapy than with inhaled corticosteroid monotherapy at the same or increased dosage, their short duration precluded definitive analysis of effects on rates of asthma exacerbation. When the studies were grouped together and subjected to meta-analysis, however, these studies collectively suggested that the combination of a LABA and an inhaled corticosteroid decreased the rate of asthma exacerbations overall.
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Posted by James
The LABAs are approved for chronic maintenance therapy of asthma, chronic obstructive pul¬monary disease and exercise-induced bronchospasm (EIB). Numerous trials have demonstrated the superiority of maintenance therapy with an inhaled LABA (administered twice daily) to maintenance therapy with an inhaled short-acting beta-2 agonist (administered four times daily). Therapy with LABAs improves lung function, bronchial hyperre-sponsiveness and symptom control during chronic administration. The LABAs also provide superior control of asthma with fewer adverse effects than sustained-release theophylline. However, the LABAs are less effective than low-dose inhaled corticosteroids as monotherapy for persistent asthma, particularly in preventing asthma exacerbations. In the studies comparing monotherapy with LABAs to inhaled corticosteroids, no improvement in bronchial hyperresponsiveness compared to placebo was noted, and one 12-month trial in children reported a decrease in lung function and increase in bronchial hyperresponsiveness for LABA therapy. However, there was no placebo group and the differences between active treatments were similar to those seen in the other studies that showed no difference in these outcomes from the placebo control group. This suggests the changes were most likely a result of patients not receiving the inhaled corticosteroid as opposed to the putative effect of LABAs on worsening asthma.
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Posted by James
LABAs differ from short-acting inhaled beta-2 agonists principally in having large side chains, increasing their lipophilicity. The greater water solubility of short-acting inhaled beta-2 agonists, such as albuterol, leads them to diffuse away from the beta-2-adrenergic receptors, limiting their duration of action. The greater lipophilicity of formoterol and salmeterol facilitates their partitioning and retention in the phospholipid region of the cell membrane lipid bilayer, prolonging the duration of action.
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Posted by James
National and international guidelines for the management of asthma concur on the goals of therapy (Table 1) and on the components of the care necessary to achieve them (Table 2). The components of care involve eliminating or avoiding disease exacerbating factors, monitoring, education and pharmacotherapy. The guidelines agree that pharmacotherapy should consist of the treatment that can most effectively reduce symptoms, prevent exacerbations and maintain lung function as near to normal as possible while producing the least amount of adverse effects.
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Posted by James
The role of inhaled beta-2 agonists in the management of asthma has changed significantly over the last several years. This review outlines the most recent understanding of the pathophysiology of asthma and the studies that define the roles lhat both short- and long-acting beta-2 agonists play in therapy for this disease. A concentration on the clinical pharmacology and genetic implications for clinical use of this class of drugs in accordance with the national and international guidelines are described.
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Table 2 and Table 3 list age-specific incidence rates of colorectal cancer in California from 1988-1995 for men and women, respectively, of each of four racial and ethnic groups. Age-specific colorectal cancer incidence rates were highest in black men and lowest in Latino women. For most ages between 45-85, the rank of incidence rates was consistent (black men > white men > Asian men > black women > white women > Latino men > Asian women > Latino women).
