The Therapy for Urinary Tract Infection - Assignment Example

Pharmacology Student’s Name Institutional Affiliation Pharmacology PART A 1. Which antibacterial agent(s) would be effective in the therapy of Mr BT’s urinary tract infection? (4 marks) The microbiology report shows that Pseudomas aeruginosa is the bacteria responsible for the urinary tract infections. As a result, therapy for Mr. BT should be able to eliminate or kill the bacteria identified. The antibacterial agent(s) chosen should be sensitive to the bacteria. From the microbiology report, cephalexin and gentamicin are the antibacterial agents sensitive to Pseudomas aeruginosa. Therefore, they should be used for the therapy. 2. State the mechanisms of action of each of these agents. (4 marks) Gentamicin is an aminoglycoside antibiotic used in the treatment of several bacterial infections. It is best used to treat those infections caused by Gram-negative organisms. Like any other aminoglycoside, gentamin mechanism of action involves the inhibition of the synthesis of proteins, which in turn activates ribosomal subunit to stop the growth of microbes. Cephalexin forms part of a group of drugs known as cephalosporin antibiotics (Cerner Multum Inc, 2009). Its mechanism of action involves preventing the formation of rigid cell of microbes making it easier to kill the dividing bacterial cells. 3. Outline the pathophysiology underlying Mr BT’s hypersensitivity to penicillin (4 marks) Drug hypersensitivity triggers antibody production in patients (Delves, 2014). Mr. BT’s medical history shows he is hypersensitive to penicillin. As a result, penicillin will activate antibody production in his immune system. Like many drugs, penicillin will act as haptens, which bind to serum or cell-bound proteins. The proteins become immunogenic due to the binding triggering anti-drug antibody production (Delves, 2014). The T-cells would respond against the drug. The immune response causes cross-reaction with other drugs within the same group. 4. Given the fact that Mr BT is allergic to penicillins, is cephalexin therapy contraindicated here? (3 marks) Yes. Cephalexin therapy is contraindicated in MR.BT’s treatment. Cephalexin belongs to the cephalosporin antibiotics that are known to have cross-allergic reactions to penicillin sensitive patients. Therefore, cross-sensitivity reaction to cephalexin can cause adverse allergic reactions to the patient (University of Illinois at Chicago, 2011). Although it is difficult to quantify the cross-sensitivity reaction between penicillin and cephalosporin, it should be administered under precautions. PART B 1. Describe the mechanism of action of the corticosteroids and indicate the adverse effects that require monitoring during treatment with these drugs. (6 marks) Dexamethasone used in the initial therapy of KY belongs to the corticosteroids. Dexamethasone is used as anti-flammatory and immune suppressant. It belongs to the corticosteroids that control immune system responsible for treating inflammations. Dexamethasone diffuses through the cell membrane and binds to glucocorticoids via its cytoplasmic receptors. The binding affects gene transcription and synthesis of proteins in DNA. As a result, leukocytes are inhibited from the inflammation point, immune system response to humoral is suppressed, and functional changes are made to the mediator of response to inflammation. The adverse effects of dexamethasone may include hypertension, changes in mood, insomnia, anxiety, depression, and acne (U.S. National Library of Medicine, 2010). All these side effects require monitoring during the use of dexamethasone drug, and severe symptoms needs medical care. 2. To which cytotoxic drug groups do each of the drugs in the case study belong? (5 marks) Cytotoxic drugs used include vincristine, L-asparaginase, daunorubicin, methotrexate and cytarabine. Vincristine belongs to cytotoxic group of vinca alkaloids, and it works by impeding the growth of cancer cells in the body (U.S. National Library of Medicine, 2013). L-aspariginase is classified under enzymes, and it is an antineoplastic chemotherapy drug. Daunorubicin belongs to the anthracyline family of drugs. Methotrexate is classified as antimetabolites drugs, and they reduce the synthesis of blood cells in the bone marrow. Cytarabine is also classified as antimetabolites. 3. Describe the mechanism of action of each of the drug groups identified in question Antibiotic Type Cytotoxic Agent (5 marks) The function of vincristine as antitumor in the treatment of cancer is due to its ability to inhibit mitosis at metaphase through interaction with tubulin (Chemocare, 2011). As a result, prevents cells division that makes it useful in cancer treatment. L-asparaginase mechanism of action involves its ability to inhibit the synthesis and circulation of plasma asparagines that are essential for leukemia cells survival. Shortfall on external circulating asparagines reduces the number of leukemia cells that eventually die. Daunorubicin has antimiotic activity by intercalating with DNA pair bases, and inhibits the activities of topoisomerase II by stabilizing its complex with DNA (Sanofi-Aventis U.S. LLC, 2014). These affects disrupt the activity of both DNA and RNA, which reduces the production of proteins. As a result, leukaemia cells do not divide and eventually die. Methotrexate stops the division of leukaemia cells by replacing folic acid in the process that synthesizes purines and pyrimidines. Folic acid reductase instead bind with methotrexate as it would with folic, and subsequently, stops the synthesis of DNA and minimizes cell division. Cytarabine is anti-metabolite like methotrexate. Cytarabine incorporate itself inside DNA destroying it directly. As a result, it inhabit cell division by interfering with DNA polymerase thus disrupt cell growth and the cells eventually die. 4. What are the common immediate and delayed adverse reactions associated with cytotoxic drugs? (4 marks) Cytotoxic drugs do have adverse reactions to users, which may vary from one patient to another. The most common immediate side effects include nausea and vomiting, fever, allergic reactions, and skin necrosis, among others. In the long run, cytotoxic drugs can destroy healthy and normal cells, and cane result into extensive necrosis of subcuteneous tissues and skin (Thakur et al., 2008). 5. Describe the clinical management of a client with increased susceptibility to infection. (5 marks) Susceptibility to infections indicates weak blood cells in the body. A client susceptible to infection may develop bone marrow depression or suppression. This may result due to chemotherapy or use of drugs that affect the immune system of the body. The client’s condition should be managed closely and regularly by monitoring the symptoms of bone marrow depression. Low red blood cells characterized by fatigue, pale skin, and dizziness may indicate bone marrow suppression. Reduced white blood cells results in low immunity with symptoms such as rash, fever and chills, and frequent infections should also indicate bone marrow depression. A client with mentioned symptoms should manage the condition by avoiding uncooked food, avoiding strenuous activities, and should increase protein consumption. In addition, the client should undergo regular clinical examination for the level of blood cells. The client should also receive antibiotics to treat infections that have already set in. 6. To which antimicrobial drug group does doxycycline belong? Is it considered a bactericidal or bacteriostatic agent? Explain. (3 marks) Doxycycline belongs to the tetracycline antibiotics. Bactericidal drugs inhibit multiplication of bacteria by killing them while bacteriostatic disrupt the reproductive mechanism of bacteria and affect their growth, which lead to their death. However, doxycycline inhibits the synthesis of bacterial protein, which in turn affect bacteria reproduction and growth. As a result, doxycycline is considered a bacteriostatic agent. 7. Define the term ‘antimicrobial drug spectrum of activity’. What is the spectrum of activity of doxycycline? Why choose a drug with this spectrum of activity? (2 marks) The term antimicrobial drug spectrum of activity can be defined as the range of species of bacteria that are affected by a chosen drug. The spectrum of activity of a drug can be classified into narrow, intermediate, or broad spectrums. Doxycycline can be classified as a broad-spectrum drug given the KY was treated with the drug for bone marrow depression. PART C 1. What is the rationale for the use of fibrinolytic drugs in acute myocardial infarction (AMI)?  Are there any constraints regarding the timing of administration of these drugs in AMI? (4 marks) Acute myocardial infarction (AMI), which is also known as a heart attack is caused when blood flow to the heart is blocked by a blood clot (thrombus) in the coronary artery. Early treatments are administered to reduce the myocardial damages. As a result, fibrinolytic therapy is carried out to restore the blood flow in the coronary artery by dissolving the thrombus formed (Aylward, 2010). The speed of administering these drugs is essential in saving lives. The longer it takes, the higher the chance of a complete heart failure. 2. Compare and contrast the mechanisms of action of the fibrinolytic drugs streptokinase and aspirin. (3 marks) Streptokinase is an enzyme that secretes streptococci that triggers plasminogen to produce plasmin. Plasmin produces fibrin, which is a constituent of thrombi that help in stopping bleeding. The excess plasmin produced by streptokinase goes in dissolving the unwanted blood clots in the arteries. Like streptokinase, aspirin helps in preventing further blood clot. However, it does not activate production of plasmin, but it inhibits platelet activation (American Heart Association, 2015). As a result, the blood flow is maintained by preventing the platelet from clumping together. 3. What adverse reactions should be monitored during and after fibrinolytic drug therapy? (3 marks) During fibrinolytic drug therapy, patients may experience bleeding in parts of the body. Older people may experience excessive bleeding. Sudden and severe headache is also common during the therapy. Some patients may feel dizzy, as well. After the therapy, patients may experience constipation, pain or swelling in the stomach, and stiff, painful or swollen joints. 4. Describe the mechanism of action of the antidysrhythmic agent amiodarone.  To which Vaughan Williams antidysrhythmic drug class does it belong? (4 marks) Amiodarone mechanism of action follows all of the four classes of Vaughan Williams antidysrhythmic drugs (Campbell, 2005). As class I, it blocks sodium and potasium channels. As class II, it provides noncompetitive antisympathetic action. Its main function, which falls in class III, is that it prolong repolarization of cardiac action potential. Finally, as class IV, it blocks the calcium channel. Although amiodarone exhibits the mechanism of action of all the four classic Vaughan Williams, it belongs to a Class III antiarrhythmic drug (Campbell, 2005). 5. Compare and contrast the actions of heparin and streptokinase (3 marks) Similar to streptokinase as discussed in question two above, heparin action is to stop blood clotting. Whereas streptokinase activates production plasmin that produces fibrin the helps in preventing clotting, heparin prevents clotting by inactivating clotting proteinase. Proteinase are inactivated when it reacts with antithrombin-heparin complex. In addition, heparin may promote thrombin inactivation by heparin cofactor II. 6. Outline the pathophysiology of heart failure (4 marks)   Heart failure or heart attack is caused when adequate blood supply to the heart stops. The blood flow may stop or be inadequate due to the blood clot in the coronary artery. When coronary artery ruptures, inner part is exposed leading to thrombosis. Thrombosis forms thrombus that blocks blood flow through the injured coronary artery leading to heart attack. A person under heart attack may experience chest pain, anxiety, and shortness of breath. 7. Describe the mechanism of action of ACE inhibitors and indicate why they are a drug of choice in heart failure (4 marks) ACE inhibitors mechanism of action involves the inhibition of conversion of angiotensin-I to angiotensin-II. Angiotensin-II vasoconstrict the blood vessels, which minimizes the blood flow to the heart. When the production of angiotensin-II is inhibited, ACE inhibitors promote vasodilation of blood vessels. In addition, the actions of ACE inhibitors enhance the production of aldosterone that promotes water and sodium retention. ACE inhibitors are drugs of choice for heart failure because rarely cause side effect to patients. 8. Pulmonary oedema is caused by alterations in fluid distribution between pulmonary blood vessels and the lung tissue.  Using fluid dynamics and changes in fluid pressure, explain the link between heart failure and pulmonary oedema. (3 marks) The heart is responsible for pumping blood from every part of the body to the heart. When the heart cannot sufficiently pump blood, blood in the artery back up to the veins taking the blood to the lungs. As the high pressure builds in the veins, the blood is forced into the open space in the lung (alveoli). The fluid in the alveoli reduces the normal oxygen supply to the blood leading to shortness of breath. 9. Compare and contrast the actions of the loop and thiazide diuretics (4 marks) Diuretics are drugs used to pass out more water from the body via kidney. The loop diuretics such as frusemide are used to enable more be released from the body to treat pulmonary oedema. Loop diuretics inhibit the salts transportation in the ascending loop of Henle. The salt variation in the system ensures only a small amount of are reabsorbed into the body, and reduces blood volume in the vessel. Like loop diuretics, thiazide diuretics ensure kidney pass out more fluid. It inhibits the reabsorption of sodium and calcium ions that ensure only a minimal amount of water are reabsorbed, and the majority released through the kidney. 10. At what stages do the diuretics and the peripheral vasodilators interrupt the pathophysiology of heart failure? (3 marks) The diuretics can only interrupt the pathophysiology of heart failure in the early stages when a person is experiencing shortness of breath, and high blood pressure. However, the heart failure progresses, other drugs are used alongside diuretics. The peripheral vasodilators interrupt the pathophysiology of heart failure in the early stages of the condition. However, the first dose of vasodilators is administered when a patient in haemodynamically stable. References American Heart Association (2015). Aspirin and heart disease. Available from http://www.heart.org/HEARTORG/Conditions/HeartAttack/PreventionTreatmentofHeartAttack/Aspirin-and-Heart-Disease_UCM_321714_Article.jsp Aylward, P. (2010). Acute myocardial infarction: Early treatment. Available from http://www.australianprescriber.com/magazine/19/2/52/4 Campell, T.J.(2005). Amiodarone. Available from http://www.australianprescriber.com/magazine/28/6/150/4 Cerner Multum, Inc (2009). Cephalexin. Available from http://www.drugs.com/cephalexin.html Chemocare (2015). Vincristine. Available from http://chemocare.com/chemotherapy/drug-info/Vincristine.aspx Delves, P.J., 2014. Drug hypersensitivity. Available from http://www.merckmanuals.com/professional/immunology-allergic-disorders/allergic-autoimmune-and-other-hypersensitivity-disorders/drug-hypersensitivity Sanofi-Aventis U.S. LLC (2014). Daunorubicin. Available from http://www.drugs.com/pro/daunorubicin.html Thakur at al. (2008). Extravasational side effects of cytotoxic drugs: A preventable catastrophe. Indian Journal of Plastic Surgery, 41(2), 145-150. doi: 10.4103/0970-0358.44923 University of Illinois as Chicago (2011). Cross sensitivity between penicillins and cephalosporins. Available from https://www.uic.edu/pharmacy/services/di/crossens.htm U.S. National Library of Medicine (2010). Dexamethasone oral. Available from http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682792.html U.S. National Library of Medicine (2013). Vincristine injection. Available from http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682822.html Read More