Salbutamol Vs Corticosteroids

In the treatment of asthma, two drug groups are at the forefront, β2-agonists (like salbutamol) and corticosteroids. Salbutamol is a β2-agonist and a physiological antagonist of bronchoconstriction and is often prescribed in an “as required” manner in the relief of symptoms (Taylor and Hancox, 2000). Salbutamol acts on a g-protein coupled receptor (GPCR) which, through a biochemical intracellular cascade ends with activation of protein kinase A, which then phosphorylates many regulatory proteins (Mcgraw and Liggett, 2005 and Johnson, 2004). Corticosteroids are steroid hormones that target the intracellular glucocorticoid receptor (GR) (figure 1). This can lead to up or down-regulation of gene transcription. It can also influence transcription factors directly in the cytosol to reduce proinflammatory effects of the associated transcription factors (Johnson, 2004). Since salbutamol and other β2-agonists and corticosteroids are often prescribed simultaneously for chronic asthma, two questions need to be asked: 1) Are there positive effects between corticosteroids and β2-agonists justifying simultaneous prescription? Or 2) Are there negative effects providing a reason for the overall increase in asthma morbidity in most western countries in the last 30 years despite increased usage of the two therapies (Sears, 1997 and Taylor and Hancox, 2000). …show more content…
Glucocorticoids have been found to upregulate β2-adrenoceptors that were downregulated. This is achieved by increasing the transcription rate of the beta receptor gene which leads to more receptors and increased sensitivity to β2-agonists (Johnson, 2004). Another study illustrated this effect even after high doses of short-acting β2-agonists which would otherwise have left them desensitised (Hadcock et al., 1989). This is of significant therapeutic importance as it should allow for continued dosage regimens without desensitisation of