Chapter 4: Patient-Focused Drug Therapy & Cultural Care

For pediatric patients, distinct physiological immaturities—such as reduced gastric acidity, slower peristalsis, and lower liver enzyme activity—significantly impact all phases of pharmacokinetics (absorption, distribution, metabolism, and excretion). Specialized dosage calculations are mandatory, with Body Surface Area (BSA) being the most accurate method, alongside common weight-based formulas (mg/kg). Drug therapy during pregnancy is complex, as fetal exposure occurs primarily via placental diffusion, with the highest risk for developmental anomalies concentrated in the first trimester; maternal liver and kidney function, as well as drug properties, are critical determinants of fetal risk. Similarly, drug transfer to the infant via breast milk requires a careful risk-benefit analysis, considering factors like drug fat solubility and molecular weight. In older adults (typically 65 years and older), age-related organ decline—including decreased cardiac output, reduced kidney function (lower Glomerular Filtration Rate), and decreased hepatic blood flow and enzyme production—prolongs drug half-life and increases the risk of toxicity. This population is highly susceptible to polypharmacy, which dramatically raises the likelihood of adverse drug interactions. Healthcare providers utilize clinical tools like the Beers Criteria to identify potentially inappropriate medications (PIMs), adhering to the dosing principle of "Start low and go slow." Finally, the chapter explores ethnocultural influences, introducing the concept of drug polymorphism, which encompasses genetic factors like varying Cytochrome P450 enzyme levels and acetylator status (rapid vs. slow metabolizers), explaining differential drug responses across ethnic groups. Comprehensive nursing assessment must incorporate these age, genetic, and cultural variables, including the use of traditional remedies and specific health beliefs, to ensure safe and individualized drug administration throughout the nursing process.