The course notes provided information that was sufficient to answer all questions.
1. Why is it important to control plasma lipid levels? Describe the mechanism of action of cholestyramine and lovastatin.
It is important to control plasma lipid levels because a decrease in plasma concentration of LDL-cholesterol can decrease the risk of coronary heart disease. Cholesterol is transformed to bile acids in the liver. Then, the bile acids are excreted into the intestine, where they are reabsorbed. Cholestyramine is a large, insoluble, and positively charged resin, which binds to the negatively charged intestinal bile acids and prevents their reabsorption. The resin also increases the excretion of these bile acids, which leads to the increased
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Drugs that alter sodium and water balance like Diuretics (eg. Hydrochlorothiazide) reduce the volume of blood by promoting the kidney’s excretion of salt and water, as well as decreasing the blood vessel stiffness or resistance. Drugs that decrease sympathetic nervous system activity like beta-blockers (eg. Propranolol) synthesize blockade of beta-adrenergic receptors in the heart and other organs in order to reduce cardiac output or the amount of blood the heart pumps. Vasodilators like calcium channel blockers (eg. Nifedipine) reduce the amount of extracellular calcium that goes into cells of the vascular smooth muscle. This results in reduced intracellular calcium, which causes arteriole relaxation, less arteriole resistance, and a decreased blood pressure.
3. Antibiotic resistance is a common problem in the treatment of infectious diseases. What measures can be taken to reduce the emergence of antibiotic resistant strains of
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However, the criteria used for the safety evaluation of food additives need to be very stringent as it may affect the entire population. In the case of food additives, health professionals are not available to give advice to consumers unlike that of OTC drugs. Food additives are typically consumed throughout the lifetime of the entire population. This means its consumption is at a higher risk than an OTC drug, which is taken for less than two weeks. Another reason for the stringent rules with food additives is because young children can be exposed during vulnerable periods. On the other hand, some OTC drugs have strong warnings that they are not for children’s consumption. Also, food additives are not essential for life as in the case of some OTC drugs, so it is important they do not lead to the detriment of life. Last, food additives are consumed without much thought even though they are listed on food labels. Therefore, it is up to their stringent regulations to look out for the