N104: Essentials of Nursing Care - Health Safety

N104: Essentials of Nursing Care – Health Safety Study Guide • Absorption: This is the process of a substance entering blood circulation. The route of the administration is one of the factors that determine the speed of the absorption, with the parenteral (injections) route typically providing the most rapid absorption. For parenteral medications, IV administration provides the most rapid method of absorption. Because of the high vascularity of the mucous membranes, medications are rapidly absorbed through the nose, respiratory tract, or mouth. Liquids are more rapidly absorbed than a solid form, which must first be dissolved. • Distribution: This is the dispersion or dissemination of substances throughout the fluids and tissues of the body. The speed of distribution is affected by the patient's general health status, the amount of blood supply in an area, and any physiological barriers that may impede the movement of the medication through the body. • Metabolism (or biotransformation): This is the irreversible transformation of parent compounds into daughter metabolites. This process often occurs in the liver for transformation before being released to the other body tissues. This is the reason liver function tests (LFTs) are often done prior to the administration of toxic medications. o The onset of the medication is the time after administration to producethe expected effect. o The blood level of a medication is the amount that is circulating in the body at a point in time. o The peak level is the point at which the blood level of a medication is at its highest point. o The trough level is the point at which the blood level of a medication is at its lowest point. o The half-life of a medication is the time needed to metabolize half of the medication's concentration. o The duration is the time during which the medication is at a high enough levelto produce a therapeutic response. • Excretion (or elimination): This is the elimination of the substances from the body. In rare cases, some drugs irreversibly accumulate in body tissue. This process most often occurs through the kidneys, but may also occur through the lungs or intestinal tract. Elderly patients or those in renal failure may have decreased ability to excrete medications, which prevents accumulation of the medication and possible toxic effects. Drug Actions and Effects Medications are given to cause a physiological change in the body. Drug actions and effects can be classified as either therapeutic or undesired. Therapeutic Actions or Effects A therapeutic action or effect is achieved when the medication does what it is supposed to do. Therapeutic effects or actions are often classified as: • Curative, when the intent is to cure a condition or disease (e.g., through the useof antibiotics to kill bacteria causing thedisease). • Supportive, when the intent is to support the body’s functions until other treatment can cure the disease (e.g., using acetaminophen to reduce a fever while an antibiotic is being used to cure the disease).

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