Which medication consideration is MOST important when administering drugs to an older adult?

PHARMACOKINETICS IN OLDER ADULTS is altered in multiple ways, creating significant medication management considerations. ABSORPTION: generally less affected; gastric motility may be slowed (delayed peak effect); some medications requiring acidic environment may be affected by reduced gastric acid. DISTRIBUTION: decreased total body water (more concentrated water-soluble drugs); increased body fat proportion (fat-soluble drugs stored longer, extended duration of action); decreased serum albumin (more free drug in circulation for protein-bound medications — higher risk of toxicity). METABOLISM: decreased hepatic blood flow and enzyme activity; slower first-pass metabolism; many drugs metabolized more slowly, requiring lower doses or longer intervals. ELIMINATION: RENAL CLEARANCE is the most clinically significant change — GFR decreases approximately 1 mL/min/year after age 40; drugs cleared renally (e.g., digoxin, metformin, many antibiotics, NSAIDs) accumulate more easily; creatinine clearance (CrCl) must be estimated using Cockcroft-Gault formula using ACTUAL weight and creatinine — note that older adults may have a 'normal' serum creatinine despite low GFR due to reduced muscle mass and creatinine production. POLYPHARMACY: the term for taking 5 or more medications; very common in older adults; increases risk of: drug interactions, adverse effects, nonadherence, falls, cognitive impairment. BEERS CRITERIA: AGS (American Geriatrics Society) list of medications considered potentially inappropriate for older adults: benzodiazepines, first-generation antihistamines (diphenhydramine/Benadryl), anticholinergics, some NSAIDs, muscle relaxants. NURSING MONITORING: watch for toxicity signs of narrow-therapeutic-index drugs (digoxin — bradycardia, nausea, visual changes; warfarin — bleeding; lithium — tremors, GI upset, cognitive changes); monitor renal function; keep medication lists updated; reconcile medications at every visit.