McKenna's Pharmacology, 2e

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C H A P T E R 4  Clinical decision making in drug therapy

Physical parameters related to disease or drug effects The specific parameters that need to be assessed depend on the disease process being treated and the expected therapeutic and adverse effects of the drug therapy. Assessing these factors before drug therapy begins provides a baseline level to which future assessments can be compared to determine the effects of drug therapy. For example, if a person is being treated for chronic pulmonary disease, their respiratory status and reserve need to be assessed, especially if a drug is being given that is known to affect the respiratory tract. In contrast, a thorough respiratory evaluation would not be war- ranted in a person with no known pulmonary disease who is taking a drug with little or no known effects on the respiratory system. The nurse or midwife has the greatest direct and continued contact with the person and is in the best position to detect minute changes that ultimately determine the course of drug therapy—ther- apeutic success or discontinuation because of adverse or unacceptable responses. Identifying health problems Information gathered during assessment is analysed to arrive at some conclusions that lead to a particular goal and set of interventions. Healthcare priorities reflect identified alterations in a person’s function based on the assessment of the clinical situation. Because drug therapy is only a small part of the overall person’s situ- ation, priorities that are related to drug therapy must be incorporated into a total picture of the person. Implementation involves taking the information gathered and synthesised to plan care. This process includes setting goals and desired outcomes to assure safe and effective drug therapy. These outcomes usually involve ensuring effective response to drug therapy, minimising adverse effects and understanding the drug regimen. Three types of interventions are frequently involved in drug therapy: drug administration, provision of comfort measures and education of the person and their family. Proper drug administration Nurses and midwives must consider a series of points, or “rights”, to ensure safe and effective drug admin- istration. These are correct drug and person, correct storage of drug, correct and most effective route, correct dose, correct preparation, correct timing and correct recording of administration. See the later section on the prevention of medication errors for a detailed explana- tion of the nurse’s and midwife’s role in implementing these rights. Remembering to review each point before administering a drug will help to prevent medication errors and improve care outcomes. Medications: The Three Checks and the Five Rights of Medication Administration

for evaluating the effectiveness of the drug and the occurrence of any adverse effects. Relevant aspects of the person’s physical examination specifically related to drug therapy are discussed in the following text. Weight A person’s weight helps to determine whether the rec- ommended drug dose is appropriate. Because the recommended dose typically is based on a 70-kg adult man, people who are much lighter or much heavier often need a dose adjustment. Age People at the extremes of the age spectrum—children and older adults—often require dose adjustments based on the functional level of the liver and kidneys and the responsiveness of other organs. The child’s age and developmental level will also alert the health- care provider to possible problems with drug delivery, such as the ability to swallow pills or follow directions related to other delivery methods. The child’s develop- mental age will also influence pharmacokinetics and pharmacodynamics; the immature liver may not metab- olise drugs in the same way as in the adult or the kidneys may not be as efficient as those of an adult. As people age, the body undergoes many normal changes that can affect drug therapy, such as a decreased blood volume, decreased gastrointestinal (GI) absorption, reduced blood flow to muscles or skin and changes in receptor- site responsiveness. Older adults often have a variety of chronic medical conditions and can be receiving a number of medications that need to be evaluated for possible interactions. Older adults with various central nervous system disorders, such as Alzheimer’s disease or Parkinson’s disease, may develop difficulty swallowing and might require liquid forms of medication. Through- out this book, Drug Therapy Across the Lifespan features present information related to the drug class being discussed as it pertains specifically to children, adults and the older adult population. These boxes high- light points that the nurse and midwife should consider to assure safe and effective therapy in each age group.

Safe medication administration

Review the monographs in a drug guide or handbook for specific parameters to be assessed in relation to the particular drug being discussed. This assessment provides not only the baseline information needed before giving that drug, but also the data required to evaluate the effects of that drug on the person. This information should supplement the overall assessment of the person, which includes social, intellectual, financial, environmental and other factors.