Asthma being a chronic inflammatory air borne disease caused by genetic and environmental factors seems to affect 5.4 million people including 1.1 million children and 4.3 million adults in UK in 2014 (Asthma UK, 2015). This study concentrates on treating asthma with inhalers containing corticosteroids as the most effective drug. With reports from NHS (National Health Service) England depicting an expenditure of £1 billion a year for treatment and care of asthma patients and a loss of 1.1 million working days due to lungs or breathing problem a correct information and application of the inhaler treatment for asthma is highly significant.
Site of action of inhaler:
The inhaled corticosteroids include flunisolide (FLU) (Aerobid), mometasone (Asmanex), flucticasone (Flovent HFA), ciclesonide (Alvesco), budesonide (Pulmicort Flexhaler) and beclomethasone (Qvar). As stated by Buckle and Smith (2013), these inhalers acts by binding the active glucocorticoid receptors bound to chaperone proteins with co-activators and activate histone deacetylase to transcription complex, which are activated due to asthmatic conditions. The corticosteroids inhibit many inflammatory protein syntheses through gene suppression.
Drug delivery and absorption of corticosteroid inhalers and their significance:
The corticosteroids inhalers are delivered directly into the lungs of asthma patients through a hand-held device as an aerosol canister, nebulizer, spacer or a mouthpiece or mask. (Voshaar et al. 2014) highlight its importance in reducing the potential side effects of the drug. Delivery of this drug through inhaler is generally once or twice with a gap of 12 hours each day. Absorption of corticosteroids varies distinctly on its use or delivery methods. These corticosteroids for asthma treatment work through lung absorption into systemic circulation. Due to high lipohilicity of fluticasone, it undergoes rapid absorption than budesonide (Corticosteroids and Society, 2015).
Uptake, metabolism and elimination of inhaled corticosteroids from the body:
Inhaled corticosteroids uptake takes place mainly through devices and moves in the body through the air tracts of lungs. The metabolism of the corticosteroids initiates with its inhalation into lungs through airway mucosa, absorbed through alveolar surface. Part of the drug deposited in the oropharynx undergoes absorption from gut for first-pass metabolism in liver (Babu et al. 2014). Elimination of these drugs through liver has a maximum rate of ~90 L.h-1. It removes any traces of drug left in mouth. The body eliminates the rest of the metabolized corticosteroids through absorption in the gastro-intestinal tract.
Risks of inhaled corticosteroid treatment:
A major and common side effect of using corticosteroid inhaler is the induced Cushing’s syndrome in asthma patients. Foster et al. (2014) identifies the systemic side effects of these drugs on using them for a long-term. The systemic side effects include cortisol suppression, adverse ocular and dermal effects, and reduced growth rate in children, cataract, glaucoma, metabolic abnormalities, psychiatric disturbances and steroid-induced osteoporosis. Moreover, these drugs also seem to produce local risks of dysphonia, cough, oropharyngeal candidiasis and pneumonia.
As per the view of LoÌˆtvall and Busse (2012), inhaled β2-agonists acting as bronchodilators when inhaled with corticosteroids effectively control asthma through synergizing effects. Corticosteroids increase expression of β2-adrenergic receptors in lungs while, the β2-agonists assist corticosteroids in nuclear translocation of glucocorticoid receptors enhancing inflammatory gene suppression.
The corticosteroids are highly expensive treatment drugs for asthma. Patients receiving treatment with FLU, beclomethasone dipropionate (BDP) and TAA (triamcinolone acetonide) depict higher healthcare charges payment than those with FP (fluticasone propionate) (Altaf and Zubedi, 2014).
The high plasma protein binding of the inhaled corticosteroids enhances the therapeutic index. The reduced oral bioavailability of corticosteroids as budesonide and fluticasone propionate also increases their therapeutic indices (Daley-Yates, 2015). Researches show that FP possesses highest half-life than BUD and BMP indicating better effectiveness of the BUD and BMP than FP. Higher systemic clearance of the corticosteroids indicate higher therapeutic index as BUD and FP revealing rapid systemic clearance of 84L/h and 69 L /h. However, BMP clearance rate of 150 L/h reflects its lower effectiveness (Medscape.org, 2015).
Administration of the correct and relevant drug dose as per the need and conditions of the patient keeping in mind the minimum effective concentration and the maximum safety concentration is highly important as any change in them result in severe adverse effects on the patients (Refer to Appendix 1). As higher doses depict association with systemic effects and expense, hence close concern and care while changing the drug administration is significant. However, the dosage of the inhaled corticosteroids needs constant changes as per the asthma conditions of the patients. For instance, during an upper respiratory tract infection as common cold, dosage needs to increase and again lower it after recovery from cold (Asthma.partners.org, 2015).
Review of drug use to manage asthma:
The inhaled corticosteroids for treating asthma work effectively through systemic absorption. In UK, it finds application as the first-line therapy for treating asthma patients. However, it works efficiently when administered in combination with the bronchodilators as β2-agonists. Foster et al. (2014) opined that the treatment could need up to 3 months time to depict effects and reach an optimal medical status over the control of asthma conditions in patients. It is evident from the study that the dosage of the inhaled corticosteroids for treating asthma needs to be at the minimum level possible. The inhaled corticosteroids show the capability of acutely suppressing the airway hyperfusion, which is closely associated with asthma. Studies reveal their efficiency in decreasing airway blood flow through modulation of nor-epinephrine-mediated control of vascular tone.
This study reflects the effectiveness along with the risks associated with using inhaled corticosteroids in the asthma patients. Administering these drugs in combination with bronchodilators seems highly effective. It is vital to prescribe the optimal dosage for the patient with regular checks for the need of any change in dose. The study also highlights the high expense of the inhaled corticosteroids in treating asthma patients in context of UK. The consideration of the risks as systemic and local side effects emerges as the eminent concerns of the treatment procedure. Hence, the inhaled corticosteroids depict high efficacy through their use as the first-line treatment process for asthma patients in UK.
Altaf, M. and Zubedi, A. (2014). Cost-effectiveness analysis of combined inhaled corticosteroids and bronchodilators for severe and very severe COPD patients in a Teaching Hospital. IOSR Journal of Pharmacy (IOSRPHR), 4(6), pp.12-23
Asthma UK, (2015). Asthma UK | Asthma facts and FAQs. [online] Available at: https://www.asthma.org.uk/asthma-facts-and-statistics [Accessed 6 Apr. 2015]
Asthma.partners.org, (2015). Asthma and Inhaled Steroids. [online] Available at: https://www.asthma.partners.org/NewFiles/InhaledSteroids.html [Accessed 6 Apr. 2015]
Babu, K., Kastelik, J. and Morjaria, J. (2014). Inhaled corticosteroids in chronic obstructive pulmonary disease: a pro-con perspective. British Journal of Clinical Pharmacology, 78(2), pp.282-300
Buckle, D. and Smith, H. (2013). Development of Anti-Asthma Drugs. Burlington: Elsevier Science
Corticosteroids, S. and Society, P. (2015). Safety of Inhaled Corticosteroids (ATS Journals). Proceedings of the American Thoracic Society. [online] Available at: https://www.atsjournals.org/doi/full/10.1513/pats.200402-016MS#.VSIVGvmSzTo [Accessed 6 Apr. 2015]
Daley-Yates, P. (2015). Inhaled corticosteroids: potency, dose equivalence and therapeutic index. British Journal of Clinical Pharmacology, p.n/a-n/a
Foster, J., Schokker, S., Sanderman, R., Postma, D. and van der Molen, T. (2014). Development of a brief questionnaire (ICQ-S) to monitor inhaled corticosteroid side-effects in clinical practice. Allergy, 69(3), pp.372-379
LoÌˆtvall, J. and Busse, W. (2012). Advances in combination therapy for asthma and COPD. Chichester, West Sussex: John Wiley & Sons
Medscape.org, (2015). Inhaled Corticosteroids: Is There an Ideal Therapy?: Inhaled Corticosteroids: Is There an Ideal Therapy?. [online] Available at: https://www.medscape.org/viewarticle/467714 [Accessed 6 Apr. 2015]
Voshaar, T., Spinola, M., Linnane, P., Campanini, A., Lock, D., Lafratta, A., Scuri, M., Ronca, B. and Melani, A. (2014). Comparing Usability of NEXThaler Â® with Other Inhaled Corticosteroid/Long-Acting Î² 2 -Agonist Fixed Combination Dry Powder Inhalers in Asthma Patients. Journal of Aerosol Medicine and Pulmonary Drug Delivery, 27(5), pp.363-370
White, P., Thornton, H., Pinnock, H., Georgopoulou, S. and Booth, H. (2013). Overtreatment of COPD with Inhaled Corticosteroids - Implications for Safety and Costs: Cross-Sectional Observational Study. PLoS ONE, 8(10), p.e75221