McKenna's Pharmacology, 2e

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P A R T 1  Introduction to nursing pharmacology

History The person’s history is an important element of assessment related to drug therapy because their past experiences and illnesses can influence a drug’s effect. Knowledge of this important information before begin- ning drug therapy will help to promote safe and effective use of the drug and prevent adverse effects, clinically important drug–drug, drug–food or drug–alternative therapy interactions and medication errors. Relevant aspects of the person’s history specifically related to drug therapy are discussed in the following text. Chronic conditions Chronic conditions can affect the pharmacokinetics and pharmacodynamics of a drug. For example, certain con- ditions (e.g. renal disease, liver disease, heart disease, diabetes, chronic lung disease) may be contraindications to the use of a drug. In addition, these conditions may require cautious use or dose adjustment when adminis- tering a certain drug. For example, a person with renal disease may require a decreased dose of a drug due to the way the drug is eliminated. The nurse or midwife should be aware of the person’s renal function to determine the person’s ability to eliminate the drug. Therefore, if renal disease is mentioned in the person’s history, the nurse or midwife should consider this factor to evaluate the dose of the drug that is prescribed. Drug use Prescription drugs, over-the-counter (OTC) drugs, street drugs, alcohol, nicotine, alternative therapies and caffeine may have an impact on a drug’s effect. People often neglect to mention OTC drugs or alterna- tive therapies because they do not consider them to be actual drugs or they may be unwilling to admit their use to the healthcare provider. Ask people specifically about OTC drug or alternative therapy use. Drug–drug interactions with OTC and prescribed drugs are highly likely and can be dangerous, resulting in ineffective drug therapy for some at-risk people. People might also forget to mention prescription drugs that they routinely take, for instance, oral contraceptives. Always ask specifically about all types of medications that the person might use. Allergies A person’s history of allergies can affect drug therapy. Past exposure to a drug or other allergens can provoke a future reaction or necessitate the need for cautious use of the drug, food or animal product. Obtain specific information about the person’s allergic reaction to deter- mine whether the person has experienced a true drug allergy or was experiencing an actual effect or adverse effect of the drug. Level of education and understanding Information about the person’s education level provides a baseline from which the nurse or midwife can determine

the appropriate types of teaching information to use. A person with a secondary school education may require materials at a different level from the person with a uni- versity degree. Gathering information about the person’s level of understanding about their condition, illness or drug therapy helps the healthcare provider to deter- mine where the person is in terms of their status and the level of explanation that will be required. It also provides additional baseline information for developing a person-focused education program. It is important not to assume anything about the person’s ability to understand based on their reported education level. Stress, disease and environmental factors can all affect a person’s learning readiness and ability. Direct assess- ment of actual learning abilities is critical for good education. Social supports People are being discharged from healthcare facilities earlier than ever before, often with continuing care needs. In addition, earlier discharges leave minimal time for teaching. Often people need help at home with care and drug therapy. A key aspect of discharge planning involves determining what support, if any, is available to the person at home. In many situations, it also involves referral to appropriate community resources. Financial supports The high cost of healthcare in general, and of medica- tions in particular, must be considered when initiating drug therapy and promoting compliance. Financial con- straints may cause a person not to follow through with a prescribed drug regimen. For example, the drug may be too expensive or the person may lack the means to get to a pharmacy to obtain the drug. In some situations, a less expensive drug might be appropriate in place of a very expensive drug. In addition, the nurse or midwife may need to refer the person to appropriate resources that might offer financial assistance. Pattern of healthcare Knowing how a person seeks healthcare provides the care provider with valuable information to include when preparing the person’s teaching plan. Does this person routinely seek follow-up care, or do they wait for emergency situations? Does the person tend to self- treat many complaints, or is every problem brought to a healthcare provider? Information about patterns of healthcare also provides insight into conditions that the person may have but has not reported or medication use that has not been stated. Physical examination It is important to assess the person’s physical status before beginning drug therapy to determine if any conditions exist that would be contraindications or cautions for using the drug and to develop a baseline