The Salbutamol - Case Study Example

Running Head: SALBUTAMOL Salbutamol: A Case Study Name Institution Date Salbutamol Salbutamol also known as albuterol is a selective short acting beta 2 adrenoceptor agonist and was the first B2 receptor antagonist to be marketed in Australia in 1968 (Anderson, 2008). The introduction of the drug shows an instant success and has been used ever since. This case study is aimed at discussing mainly salbutamol in relation to the pharmacological effects to the human body as a whole and how the drug could be put to use in various treatment plans of the patients. Mode of action of salbutamol Salbutamol is a short acting specific B2 receptor agonist which means it works by specifically acting on one type of receptor to cause an action. Basically there are two types of Beta receptors, appropriately named as the type 1 and type 2 beta receptors respectively. The location of Type 1 receptors is mostly around cardiac tissue, whereas the type 2 beta receptors are mostly located around the airways (Barnes, 1983). Salbutamol brings about the relaxation of Smooth muscles after stimulating the ß2-receptor at the cell membranes and as a result conversion of adenosine triphosphate(ATP) to cyclic adenosine mono phosphate(cAMP) ensures, this eventually brings about the activation of protein kinase that eventually causes the phosphorylation of proteins that will end up with the reduction of the amount of calcium being made available to bind with actin and myosin, it is this that will now bring about the relaxation of the smooth muscles. Salbutamol will also bring about the anti-inflammatory activity by preventing the release of inflammatory mediators. In addition, salbutamol also brings about increased mucociliary clearance rate thus preventing the obstruction of the airways (Barnes, 1983) Salbutamol being a beta type 2argonists acts on the smooth muscles on the airways and reverse the narrowing of the airways as in the case of asthma and also in chronic obstructive pulmonary disease. The other effects of the beta agonists would include the considerable reduction of coughing (Kasper, 2005). Salbutamol is also able to reduce the vascular resistance in the peripheries thus causing increased perfusion on the body. Salbutamol will also bring about the fall of blood pressures but will increase the heart rate (Raymond, 2004). By having specific beta 2 receptor stimulation you can limit the amount of cardiac side effects. This is effectively shown when compared to a drug which would stimulate both the type 1 and type 2 receptors indiscriminately, e.g. adrenaline. Salbutamol is used in relieving of broncho-spasm in patients with Asthma or Chronic Obstructive pulmonary Disease, and for acute prophylaxis against exercise induced asthma, or in situations known to induce broncho-spasm (Rossi, 2004).). This versatile drug can be given through many routes of administration. It has multiple uses in emergency, obstetric and respiratory medicine. When used in asthma the drug is most commonly administered through a metered dose inhaler [MDI] or nebulised mask. It will rarely be used orally or intravenously through an infusion (Rossi, 2004). Salbutamol MDI is routinely prescribed by a General Practitioner for the first line treatment of asthma exacerbations and asthma prophylaxis. The MDI is easy to use, can be carried easily and will give the correct dose when used effectively. Different doses are prescribed depending on severity and use. A spacer can also be used to make the inhaler give a more effective dose. As a prophylactic treatment before exercise the dose is 2 puffs on the MDI 15 minutes before exercise. For relief of Bronchospasm induced shortness of breath use 4 puffs via spacer; repeated every 4 minutes if no improvement. If still no improvement the patient is told to call an ambulance and repeat 4 puffs -every 4 minutes until ambulance arrives. In a hospital environment larger doses of Salbutamol can be used. Normally this is nebulised through a mask with doses of 2.5mg-5mg repeated according to severity and response every 15 minutes (Rossi, 2004). Inhaled selective, short-acting b2 agonists reverse mild acute airway narrowing and are sufficient treatment, alone, for mild intermittent asthma causing occasional symptoms (Rossi, 2004). Salbutamol diffuses into systematic circulation thus it will have a number of effects on different body systems. Although it is designed to specifically work on Beta 2 receptors a small amount of beta 1 stimulation will still take place to some extent. A reflex response due to systematic vasodilatation will also occur to increase perfusion of the peripheries. These two changes bring about Tachycardia and increased cardiac output to compensate for the larger vascular space and the Beta 1 receptor stimulation. Secondary to this is the patient having palpitations and possible hypotension which is evident especially in the badly compensating patients due to systematic vasodilatation. This increase in Cardiac output will bring about a higher myocardial oxygen demand. This should be taken into consideration especially when using larger doses of Salbutamol in patients with heart diseases (Rossi, 2004). Pharmacokinetics of salbutamol Salbutamol has a half life of about 3 to 5hours with a peak plasma level of 2 to 3 with bioavailability being almost to 50%constant. Modes of administration Mainly in bronchial asthma the metered dose inhaler is put into use the doses would be grouped into the initial dose and the maintenance dose. The initial dose would contain about 100 to 200 µg that is 1 to 2 puffs every 4 hours. The maintainace dose would vary but the dose could be increased to up to 400 µg (Barnes, 1983) Side effects of salbutamol Both hyperkalaemia and hyperglycaemia have been reported in patients taking Salbutamol. The effect of Salbutamol on the metabolism of potassium is complex. Salbutamol directly stimulates the transfer of potassium from extracellular fluid to the intracellular fluid by the activation sodium-potassium-dependent adenosinetriphosphatase. In addition, secretion of insulin, which has a similar effect on the transfer of potassium, is stimulated by Salbutamol. These two pathways cause a decrease in serum Potassium, which can cause cardiac arrhythmias and mortality (O’Brien et al, 1981). The risk of hyperkalaemia is low and dose dependent. Interestingly two recorded cases of Salbutamol induced Salbutamol have been recorded with low levels of the drug (Udezue et al, 1995). Beta adrenergic stimulants can produce hyperglycaemia in normal subjects, and particularly in those with acute severe asthma. This is attributed to muscle and hepatic glycogenolysis and gluconeogenesis resulting from stimulation of the B2 receptor (Dawson et al, 1995). Patients with a history of diabetes are most at risk of hyperglycaemia, with cases of DKA being documented (Puttanna et al, 2010). Another side effect of Salbutamol is the appearance of a fine muscle tremor in some patients when delivered via nebuliser or MDI, the hands being most noticeably affected. Some patients have also reported feeling more stressed or tense after larger doses of Salbutamol. These effects are doses related and are caused by direct action on skeletal muscle and not by direct Central nervous system stimulation. Another neurological side effect is the appearance of a headache post administration due to systematic vasodilatation of the arteries in the brain (Rossi, 2004). Other adverse reactions of salbutamol would vary depending on the system that has been affected. In the central nervous system, it would bring about spells of dizziness and some headaches. In the cardiovascular system, it will cause palpitations and also increased blood pressures and chest pains. In the gastrointestinal system it will bring about the feeling of nausea, heartburns and some episodes of vomiting. In the respiratory system, dyspnoea could be observed and some cases paradoxical bronchospasms. The skin will also elicit the adverse reactions and this would include some degrees of pallor and urticaria Formulations of salbutamol that are currently present in the market would include the salbutamol tablet, the nebulised salbutamol and the syrup (Barnes, 1983). Patients Health history The patients name is Jane Doe who is an 18 year old female and works as a Barista in a local coffee shop. She has a known medicinal allergy to penicillin. In her past medical and surgical history. She has a history of Asthma which was diagnosed when she was 5 years old, and she also sustained a fractured Ulna/Radius at the age 7 with a subsequent management of Open Reduction Internal Fixation under general anaesthetic. She had no other significant childhood illnesses. In her gynaecological history had menarche began at 14years and the cycle is regular and of normal volume. She has had no history of sexually transmitted infections or diseases. She uses oral contraception as a method of family planning, she uses Monofem (ethinyloestradiol 30mg) and in her obstetric history she is Para 0+0. Currently the patient complaining of shortness of breath especially during periods of physical exertion, and she gives the example of walking up stairs and states that she also feels short of breath after walking from the waiting room. She was diagnosed with Asthma at the age 5 and was prescribed Salbutamol Metered dose inhalers 100mcg. She was educated to take two puffs every 15 minutes before any exercise as a prophylaxis to prevent subsequent falling shortness of breath. The inhaler was also to be used; 2-4 puffs via spacer as needed. This medication has been working for her and she has not had any severe asthmatic attacks for the last 13 years. In her social history, Jane lives with her mother and mother’s partner in a small rural town, and is educated up to a year 10 level. She has a long term male partner in a happy, nonviolent, monogamous relationship. There is no reported history of mental illnesses or disabilities. In relation to risk taking behaviour the patient does not use tobacco. She drinks alcohol rarely, but when she does drink she drinks to excess. She denies any other illicit drug use. She has lived in the same area all her life and has never been overseas. In her family history, both of her grandparents, the paternal and maternal sides are alive and well. There is a reported history of diabetes in the family with both her mother and the maternal grandmother have type 2 diabetes mellitus, non insulin dependent which is controlled by hypoglycaemic’s. She is not the only one who is asthmatic in the family, one of her sister as a known asthmatic too. Physical Assessment finding’s with links to drugs. On general examination, Jane is in a fair general condition and she has a good nutritional status. 0n assessing the 8 general parameters, she has no jaundice, no oedema, no lymphadenopathy,no finger clubbing, nor oral thrush, some pallor, however there is some dehydration and cyanosis respectively. On Neurological assessment: Jane is Alert She is oriented in time, place and person and has a Glasgow Coma Scale reading of 15/15. She is responding appropriately to questions and does not appear to have any deficit or intellectual disability and her higher centres are normal. However the patient reports of a headache that was of insidious onset, and comes on and off with intervals of 3/10 minutes. Jane Had a mild headache this is a well documented side effect of Salbutamol (Rossi, 2004). In the Respiratory: Jane states she has had no cough, cold or flu like symptoms recently. The patient states she is mildly short of breath. She had her last dose of Salbutamol (4 puffs) 90 minutes ago. She is speaking in full sentences with a respiratory rate of 19. Upon inspection her chest is moving with respiration and the movement of the chest is equal bilaterally, there are no visible surgical or tradional markings on the chest wall, there are no congenital anomalies of the chest wall such as kyphosis or scoliosis and the jugular veins are not distended. There is some use of the accessory muscles on respiration also there is some flaring of the alae nasae.On palpation the trachea is not deviated and the chest expansion is normal. Upon auscultation no wheeze or consolidation heard, the bronchial breath sounds are normal. On percussion there is resonance. Her peak flow measure is 520 litres per minute (LPM), for her height the peak flow should be closer to 649LPM (Asthma Australia, 2005). This reduction in peak flow shows that Salbutamol is not working as affectively as a lone medication for Janes Asthma at this point. Cardiac: Jane states she has some feelings of palpitations and cannot feel her pulse bounding. Upon palpation Janes pulse is strong in character and regular with a rate of 92 beats per minute. This rate is at the top end of normal and in a young fit person could be seen as faster than normal (Newhouse et al, 1996). Her blood pressure if 127/63 which makes her normotensive for women of her age group. An Electrocardiogram is conducted and shows she is in normal sinus rhythm. In the Genitourinary and gastrointestinal: Nothing significant detected. The Skin and membranes: Patients face appears flushed all other skin surfaces normal. Patient has moist mucous membranes. Skeletal/mobility Fine motor tremors observed on the lower and upper arms, patient states this comes on after she has been using 4 puffs of Salbutamol and lasts up to 2 hours. Investigations The patient has had a blood sample taken for electrolytes and serum blood sugar. Her Potassium levels were 4.1 which are within normal limits while her blood sugar was 5.3 which are within normal limits (Rossi, 2004). Her peak flow measure was 520 litres per minute. Impression; An impression of asthma is made basing on the history of the patient difficulty in breathing, breathlessness on exertion and also the use of accessory muscles while breathing. Also after the use of salbutamol, some of the symptoms seem to have reduced significantly after the 90 minutes after administering the salbutamol for example the difficulty in breathing. Summary; The use of salbutamol has its positive and negative aspects. The positive aspects are purely based on it being receptor specific and only acts on beta 2 receptors. When salbutamol is used, the bronchoconstriction is significantly reduced also the difficulty in breathing is reduced as a result. However the use of salbutamol also has negative effects which some of which were able to be seen and felt by the patient for example its effects in the central nervous system like headache which was felt after using the salbutamol. Others included the palpitations and the increased blood pressures. However, even with the minor side effects, the positive effects of salbutamol still make it effective in the management of asthma and chronic obstructive pulmonary diseases. References A D O'BRIEN et al (1981). Hypokalemia due to salbutamol overdose. British medical journal volume 282, hypokalemia due to salbutamol overdose. Retrieved from EBSCOhost Accessed on 28th march 2011 from www.kaplanmedical.com Barnes PJ, Pride NB. Dose response curves to inhaled -adrenoceptor agonist in normal and asthmatic subjects. British Journal of Clinical Pharmacology. 1983; 15:617-82. Anderson, K. (2008). Ventolin remains a breath of fresh air for asthma sufferers, after 40 years. The Pharmaceutical Journal 279 (7473): 404-–405. Retrieved from http://www.pharmj.com/pdf/articles/pj_20071013_landmarkdrugs01.pdf.  Dawson, P, et al (1995). Acute asthma, salbutamol and hyperglycemia. Acta Paediatr; 84(3): 305–7. Dawson, P, Penna, A, Manglick, P. (1995). Acute asthma, salbutamol and hyperglycaemia. Acta Prediatr, 84:305-7. Stockholm. Newhouse, T, Chapman, R, & McCallum A, (1996). Cardiovascular safety of high doses of inhaled fenoterol and albuterol in acute severe asthma; 110 (3): 595-603 (journal article - research, tables/charts). Peak, F. (2005). National Asthma council Australia. Retrieved from http://www.nationalasthma.org.au/content/view/186/35/ Puttanna, A., Cunningham, A. & Scanlon, J. (2010), Hyperglycemia as a result of stress and possible drug interactions: a case report. Practical Diabetes International, 27: 304–305. doi: 10.1002/pdi.1507 Raymon, L (2004) Pharmacology. Kaplan medical Inc: USA Rossi, S (2004). Australian Medicines Handbook (AMH),  Oxford textbook of medicine: MIMS. Udezue, E., D'Souza, L, & Mahajan, M. (1995). Hypokalemia after normal doses of nebulized albuterol (salbutamol). American Journal of Emergency Medicine, 13(2), 168-171. Retrieved from EBSCOhost. Read More