Chapter 3: Lifespan Considerations

During pregnancy, the chapter addresses teratogenic risks with particular emphasis on the first trimester when organ systems are forming and drug exposure poses the greatest danger of developmental abnormalities. The discussion integrates FDA pregnancy category classifications and updated labeling requirements that guide clinical decision-making for pregnant patients. The section on lactation explores the mechanisms of drug transfer into breast milk and evaluates potential harm to nursing infants, recognizing that many drugs considered safe during pregnancy may accumulate in infants through breastfeeding. For neonatal and pediatric populations, the chapter explains how immature hepatic metabolism, reduced renal clearance, altered gastric pH, and increased skin permeability create heightened vulnerability to drug toxicity. Weight-based dosing calculations using milligrams per kilogram become essential rather than optional in pediatrics, reflecting the profound differences in body composition and organ function compared to adults. The chapter then addresses aging-related changes in older adults, where declining kidney and liver function, reduced cardiac output, and altered body composition shift drug absorption, distribution, metabolism, and elimination patterns. Polypharmacy in geriatric patients substantially increases the risk of adverse drug interactions and medication-related problems. The Beers Criteria is presented as an evidence-based resource for identifying medications that pose disproportionate risks in elderly patients and should generally be avoided. Throughout all age groups, the chapter emphasizes individualized nursing assessment, patient and family education tailored to developmental level, and vigilant monitoring strategies to detect and prevent adverse drug reactions. The overarching theme integrates pharmacologic principles with lifespan development, cultural sensitivity, and patient-centered care.