The Side Effects of Salbutamol - Essay Example

Asthma is a disorder in which breathing becomes very difficult due to the insufficient passage of air into the lungs. During an asthma attack there is a narrowing of the bronchi accompanied by coughing, wheezing and shortness of breath. Usually these attacks are short lived and the patient recovers, nevertheless severe attacks can sometimes prove to be fatal. The term Asthma most commonly refers to bronchial asthma or an inflammation of the bronchi, however it also refers to cardiac asthma which is the result of fluid collection in the lungs as a complication of heart failure. Bronchodilators or substances which loosen the muscle bands that tighten around the airways provide relief during an asthmatic attack. The relief is rapid and the quantity of air going in and coming out of the lungs increases dramatically. This improves the breathing. Further, mucus in the lungs is cleared and can be expectorated with ease. (WebMD, May 2006) Salbutamol is a sympathomimetic (encyclopedia.com, 2006) agent used as a bronchodilator in the treatment of asthma. Its chemical formula is C13H21NO3. Its IUPAC name is 2-(hydroxymethyl)-4-(1-hydroxy-2-tert-butylamino-ethyl)-phenol. (ChemIndustry.com, 2005) The origin of the name of this drug is [SAL (ICYLIC ACID) + BUT(YL) + AM(INO)- + -OL]. Salbutamol is a member of the adrenergic bronchodilators family and stimulates the nerves in the body with different effects. These medicines help open the bronchial tubes of the lungs, resulting in the free passage of air. It is for this very reason that these drugs are used in the treatment of the symptoms of asthma, bronchitis, emphysema and other diseases related to the lungs (Medline Plus, 19 September 2005). These drugs enable relief from cough, wheezing, shortness of breath and troubled breathing by enabling the free flow of air through the bronchial tubes. In its capacity as a short acting beta 2 agonist Salbutamol (Salbutamol.com) can be delivered to its site of action in a variety of ways. Some of these are described in the sequel. Metered Doses Inhalers are the most common method of delivery of Salbutamol as they are small and convenient to carry and deliver a specified quantity of the drug directly to the lungs. They account for three fourths of all inhaled medication in the treatment of asthma and chronic obstructive pulmonary disease. These devices are very accurate and a spacer device enhances this accuracy significantly (arap.org, 14th June, 2004). Nebulisers are another common form of delivering the drug directly to the lungs, however over a longer period of time. The inhaled forms of Salbutamol have a faster onset of action, fewer side effects and are more effective than the syrup or tablet forms. Solution (Injections + syrups) of Salbutamol can be injected by intravenous, subcutaneous or intramuscular means to treat very severe asthma attacks or inhaled. "Each millilitre of Ventolin inhalation solution contains 5 mg of Salbutamol (as 6 mg of Salbutamol sulphate) in an aqueous solution containing benzalkonium chloride. Sulphuric acid is used to adjust the pH value to between 3 and 5. Ventolin inhalation solution contains no sulphating agents and is a clear, colourless to light yellow solution. Ventolin syrup contains 2 mg of salbutamol as 2.4 mg of salbutamol sulphate in each 5 ml." (GlaxoWellcome, September 1998) Tablets and extended release tablets contain 2 or 4 mg of salbutamol as 2.4 or 4.8 mg, respectively, of salbutamol sulphate. Each Proventil Repetab or extended-release tablet contains a total of 4 mg (2 mg in the coating for immediate release and 2 mg in the core for release after several hours) of salbutamol as 4.8 mg of salbutamol sulphate. The inactive ingredients for salbutamol extended-release tablets include butylparaben, calcium phosphate, calcium sulphate, lactose, magnesium stearate, oleic acid and titanium dioxide. The slower acting extended release tablets have duration of action of at least 12 hours after a single dose. It can be used with anti-inflammatory drugs for long term control of symptoms, especially night coughs and to prevent exercise induced asthma. Salbutamol can be delivered in several different forms, namely, Salbutamol; Salbutamol sulphate, with a molecular weight of 576.7 and empirical formula C13H21NO3)2H2SO4, is a white crystalline powder, soluble in water and slightly soluble in ethanol; and Salbutamol hydrochloride. Salbutamol is delivered as a racemic mixture (+,-) salbutamol, even though S-Salbutamol is know to have a detrimental effect on asthma suffers in fact the exact opposite effect of the R Isomer, which is much more effective in the treatment of asthma. The side effects of salbutamol (The PDR Family Guide To Prescription Drugs, 2003) are generally cramps or tremors due to the drug's action on muscles, and the drug's action on beta 1 adrenoceptors in cardiac muscle, which is 500 time less binding than beta 2, cause vasodilatation with resulting effect on blood pressure and the heart. More common side effectsare aggression, agitation, cough, diarrhoea, dizziness, excitement, general bodily discomfort, headache, heartburn, increased appetite, increased blood pressure, indigestion, irritability, laboured breathing, light-headedness, muscle cramps, nausea, nervousness, nightmares, nosebleed, over activity, palpitations, rapid heartbeat, rash, ringing in the ears, shakiness, sleeplessness, stomach ache, stuffy nose, throat irritation, tooth discoloration, tremors, vomiting, wheezing and worsening bronchospasm. The less common side effectsare chest pain or discomfort, difficulty in urinating, drowsiness, dryness of the mouth and throat, flushing, high blood pressure, muscle spasm, restlessness, sweating, unusual taste, vertigo and weakness. Rare side effects on inhalation of salbutamol are hoarseness, skin rash or hives, hypokalemia, myocardial insufficiency, heart failure, angina-pectoris, hypertension, severe cardiovascular disease, diabetes-mellitus, maternal-thyrotoxicosis. Salbutamol was developed by rational design when there were no models of the -receptors, which were not characterized until the 1990s. So the researchers relied on an iterative process based on what they knew about the structure and properties of adrenaline and isoprenaline. Patients with nocturnal asthma who are clinically stable have poorer daytime cognitive performance and poorer subjective and objective sleep quality compared with normal, healthy patients.( Fitzpatrick, Engleman, Whyte, et al 1991) Asthma is incurable and drug therapies can only minimize the impact of the disease on daily functioning and well-being, thereby enhancing quality of life. Since conventional clinical outcomes alone do not directly reflect quality-of-life considerations, assessment of these parameters through questionnaires has been included in clinical trials to evaluate the full impact of treatment interventions. Treatment of nocturnal asthma symptoms has focused on sustained-release oral 2-agonists, theophylline, anti-inflammatory medications, and more recently the long-acting, inhaled 2-agonist bronchodilators, such as salmeterol xinafoate, which is a very good alternative as it produces effective bronchodilation for 12 hours after a single inhaled dose. ( Britton, Earnshaw, Palmer, 1992). Salmeterol has also demonstrated significant improvements in overall quality of life assessments compared with albuterol or placebos in patients with asthma. ( Nathan, Seltzer, Kemp, et al, 1995). The modern treatment of asthma and chronic obstructive pulmonary disease or COPD consists of inhalation therapy, (Dolovich, and MacIntyre, 2000) which is highly effective treatment with few side-effects. There are two main categories of inhaled treatment for asthma and COPD, namely, bronchodilators or acute relievers and anti-inflammatory medication or the so called controllers or preventers. Nearly all patients with asthma and COPD require short-acting bronchodilators, which constitute the main treatment for acute attacks and are lifesaving in severe attacks. In intervals between attacks, they may be needed in the day, particularly in children for whom exercise- induced asthma is common. Inhaled bronchodilators fall into three classes, viz. Beta-agonists, which constitute the main reliever treatment for asthma and COPD. Short acting beta-agonists, which include salbutamol or what is called albuterol in the United States, terbutaline, and fenoterol. They act within a few minutes, and have an effect lasting approximately 4 hours. Long-acting beta-agonists, like salmeterol and formoterol, which have an effect that may last for up to 12 hours and Anti-cholinergics including ipratropium bromide and tiotropium bromide, which are commonly used as first-line bronchodilator therapy in COPD. List of References Arap.org [14 June 2004] Metered Dose Inhalers [online] available from [20 July 2006] Britton, MG, Earnshaw, JS, Palmer, JBD (1992) A twelve-month comparison of salmeterol with salbutamol in asthmatic patients. Eur Respir J 5,1062-1067. chemIndustry.com (2005) Salbutamol [online] available from < http://www.chemindustry.com/chemicals/72632.html> [20 July 2006] Dolovich, M.A. and N.R. MacIntyre, 2000. Consensus statement: aerosols and delivery devices. Respiratory Care, 45(6), 1-22. Fitzpatrick, MF, Engleman, H, Whyte, KF, et al (1991) Morbidity in nocturnal asthma: sleep quality and daytime cognitive performance. Thorax 46,569-573. Glaxowellcome [September 1998] VENTOLIN [online] available from [20 July 2006] Healthysource.com [2003] PROVENTI [online] available from [20 July 2006] HighBeam Encyclopedia (2006) sympathomimetic drug [online] available from [20 July 2006] Medline Plus (19 September 2005) Bronchodilators, Adrenergic (Inhalation) [online] Available from [20 July 2006] Nathan, RA, Seltzer, JM, Kemp, JP, et al (1995) Safety of salmeterol in the maintenance treatment of asthma. Ann Allergy Asthma Immunol 75,243-248. Salbutamol.com All you need to know about Salbutamol. [online] available from < http://www.salbutamol.com/default.htm> [20 July 2006] webMD (May, 2006) Treating Asthma with Bronchodilators [online] available from [20 July 2006] Read More