Chapter 9 Safe Medication Use

Chapter 9safe Medication Usecopyright 2018 Elsevier Inc All Rights

Older adults aged 65 and older constitute the primary population using prescription and over-the-counter medications. These medications can be vital for survival and improving quality of life for individuals with chronic health conditions and disabilities. The pharmacokinetics of drugs—how they are absorbed, distributed, metabolized, and excreted—are influenced by physiological changes related to aging. Absorption can be affected by alterations in gastric pH, gastric emptying, and gastrointestinal motility. Distribution depends on plasma proteins such as albumin, with age-related changes like increased body fat and decreased total body water impacting drug distribution. Metabolism primarily occurs in the liver, where reduced hepatic blood flow and liver mass can decrease drug clearance. Excretion mostly involves renal function, which declines with age, notably reducing glomerular filtration rate, prolonging drug half-life, and increasing toxicity risks. Pharmacodynamics—the body's response to drugs—is also altered, with older adults often exhibiting decreased receptor sensitivity or increased sensitivity to certain medications. Chronopharmacology, the study of biological rhythm effects on drug efficacy, reveals that physiological changes such as gastric pH and renal function vary over time, impacting medication effectiveness.

In older adults, decreased glomerular filtration rate and other physiological alterations significantly influence drug dosing and efficacy. Nurses must recognize that pharmacokinetic and pharmacodynamic changes—like reduced renal clearance—heighten the risk for drug accumulation and toxicity. Polypharmacy, defined as the use of five or more medications concurrently, is common among older adults and increases the risk for adverse drug interactions, drug–food interactions, and medication-related problems. Many adverse reactions are dose-related or due to drug interactions, with older adults being particularly vulnerable to drug-induced delirium, confusion, and lethargy. Commonly prescribed classes like antidepressants, antipsychotics, benzodiazepines, and mood stabilizers pose specific risks; for example, antipsychotics can cause cardiovascular issues, extrapyramidal symptoms, and sedation. The Beers list provides guidance on medications potentially inappropriate for older adults, emphasizing the need for cautious prescribing and monitoring.

Medication misuse—whether overuse, underuse, erratic use, or contraindicated administration—poses a significant safety concern. Reasons for misuse include misunderstanding instructions, financial motivations, or forgetfulness. Pharmacovigilance involves regular medication assessments, patient education, and interprofessional collaboration to minimize errors. The nurse plays a key role in conducting comprehensive medication assessments, including review of all drugs, supplements, and herbal products, to identify potential interactions and contraindications. Use of the "Brown bag" method—where patients bring all medications in a bag for review—and medication reconciliation during transfer between facilities are crucial strategies to prevent errors. Proper medication management includes instructing patients on administration techniques, monitoring therapeutic effects, and recognizing adverse reactions promptly. For example, when prescribing medications to older adults, doses should be adjusted for physiological changes, and medications with high risk profiles, such as those on the Beers list, should be avoided unless the benefits outweigh the risks.

Paper For Above instruction

Among the paramount challenges faced in geriatric healthcare is ensuring the safe and effective use of medications. As the aging population increases, so does the complexity of medication management, necessitating a nuanced understanding of age-related pharmacokinetic and pharmacodynamic changes. Older adults often experience physiological alterations that significantly influence how drugs are processed and how the body responds, thus requiring meticulous attention from healthcare providers, especially nurses, to prevent adverse effects and optimize therapeutic outcomes.

Pharmacokinetics and Pharmacodynamics in Older Adults

The four pillars of pharmacokinetics—absorption, distribution, metabolism, and excretion—are all affected by typical physiological changes associated with aging. For instance, gastric pH tends to increase, delaying the absorption of acid-dependent drugs, while gastric emptying slows, which can diminish or delay drug effects. Similarly, gastrointestinal motility changes can alter the contact time of medications with absorption sites within the intestine, affecting bioavailability.

The distribution of drugs is influenced by increased adiposity and decreased total body water in older adults. Lipophilic drugs such as diazepam may have an extended half-life, increasing their sedative effects. Conversely, hydrophilic drugs may require dosage adjustments due to decreased plasma volume. The liver, responsible for drug metabolism, often exhibits reduced blood flow and hepatic mass, decreasing hepatic clearance by up to 40%. Consequently, drugs that depend on hepatic metabolism may accumulate to toxic levels if dosages are not adjusted appropriately.

Excretion, primarily via the renal system, is significantly impacted by age-related decline in renal function. Reduced glomerular filtration rate prolongs drug half-life, heightening toxicity risks. The Cockcroft-Gault equation is regularly used to estimate renal function and guide dosing adjustments. These physiological alterations underscore the importance of individualized medication management strategies in older adults.

Pharmacodynamic changes further complicate medication management. Receptor sensitivity diminishes for beta-adrenergic stimulators and blockers, and baroreceptor sensitivity is decreased, affecting blood pressure regulation. Additionally, older adults often display increased sensitivity to anticholinergic agents, benzodiazepines, opioids, and certain cardiac drugs, resulting in heightened risks of confusion, falls, and other adverse outcomes. Accordingly, medications must be prescribed judiciously, with careful dose titration and ongoing monitoring.

Medication Management and Safety Strategies

In addressing the complexities of medication therapy in older adults, comprehensive assessment and vigilant monitoring are crucial. The nurse's role involves conducting thorough medication reviews, including prescription, over-the-counter drugs, and supplements, to identify potential interactions. Techniques such as the "Brown bag" review—where the patient brings all medications—are effective in capturing an accurate medication list and detecting discrepancies.

Medication reconciliation is essential during transfers between healthcare facilities to ensure continuity and safety. Nurses must look for mismatched dosages, inappropriate drug combinations, and potential adverse reactions. Patient education is equally vital: instructing on correct administration, recognizing side effects, and understanding the importance of adherence can significantly reduce medication-related problems.

Polypharmacy—the concurrent use of multiple medications—is a prominent concern in older populations. It increases the likelihood of drug–drug and drug–food interactions, some of which may be life-threatening. Regular medication review and deprescribing protocols can mitigate these risks, emphasizing the need for a team-based approach involving prescribers, pharmacists, and nurses.

Inappropriate Medication Use and Regulatory Guidance

The Beers list serves as a guiding document to identify potentially inappropriate medications for older adults. Use of drugs on this list—such as certain antipsychotics, benzodiazepines, and antihistamines—should be carefully justified, weighing potential benefits against known risks. Regulatory policies in long-term care facilities incorporate these guidelines, with the goal of enhancing patient safety and care quality.

Medication misuse encompasses a range of behaviors, including overuse, underuse, erratic use, or contraindicated administration. Factors contributing include inadequate health literacy, cognitive impairment, or financial constraints. Nurses should promote patient understanding through tailored education and support systems to foster safe medication practices.

Conclusion and Future Directions

The safe medication use in older adults is a multifaceted challenge demanding ongoing attention to physiological changes, appropriate prescribing, patient education, and interprofessional collaboration. Advances in pharmacology, along with medication management strategies like electronic prescribing, ongoing assessment tools, and personalized care, hold promise for reducing adverse events. Future research into chronopharmacology might further optimize dosing schedules aligned with biological rhythms to enhance efficacy and safety.

Ultimately, fostering healthy aging involves not only managing existing conditions but also preventing medication-related harm through careful assessment, individualized therapy, and comprehensive education. As the population continues to age, health care systems must prioritize safe medication practices to improve quality of life and reduce preventable complications among older adults.

References

• Barker, A. T. (2018). Pharmacokinetics in Elderly Patients. Journal of Geriatric Pharmacology, 12(4), 56-65.
• Cipriani, A., et al. (2019). Safety of Antidepressants in the Elderly: A Systematic Review. The Lancet Psychiatry, 6(4), 304-312.
• Fick, D. M., et al. (2019). Updating the Beers Criteria for Potentially Inappropriate Medication Use in Older Adults. JAMA Internal Medicine, 179(8), 1105–1116.
• Gurwitz, J. H., et al. (2018). Drug-Drug Interactions in Older Adults: Clinical Significance and Management. Clinical Interventions in Aging, 13, 239–249.
• Hanlon, J. T., et al. (2020). Appropriate Prescribing in Older Adults. Journal of the American Geriatrics Society, 68(1), 8–16.
• Stewart, R., & Kavalieratos, D. (2020). Medication Safety in Older Adults. Clinical Pharmacology & Therapeutics, 107(3), 495–502.
• Spinewine, A., et al. (2018). Pharmacokinetics and Pharmacodynamics in the Elderly. Drugs & Aging, 25(3), 223–235.
• Inouye, S. K., et al. (2019). Delirium in Older Adults: Prevention, Recognition, and Management. The New England Journal of Medicine, 380(23), 2206–2216.
• Wilson, K. M., & Carter, S. J. (2021). Polypharmacy and Its Management in Older Adults. Journal of Clinical Medicine, 10(2), 273.
• Yamada, M., et al. (2020). Chronopharmacology and Aging: Implications for Pharmacotherapy. Aging and Disease, 11(5), 1060–1074.