A 45-year-old client with a history of heart failure and diabetes is admitted to the medical unit with dehydration and confusion. The nurse notes the client has been taking multiple medications and has poor oral intake. Which nursing intervention should be the priority to address physiological changes that may be contributing to the client's current condition?

This client presents with a classic high-risk geriatric syndrome: an older adult with multimorbidity (heart failure, diabetes) experiencing an acute change in mental status and dehydration in the context of polypharmacy. The priority nursing intervention must target the most likely underlying physiological mechanism contributing to the current condition.

Age-related physiological changes, specifically declining renal function, create a dangerous interplay with polypharmacy. Reduced glomerular filtration rate impairs the clearance of many medications and their active metabolites, leading to drug accumulation and toxicity even when standard doses are administered ^[1]. In this scenario, dehydration further compromises renal perfusion, acutely reducing the kidneys' ability to excrete drugs. This creates a vicious cycle where dehydration worsens drug clearance, leading to toxic serum levels that can manifest clinically as confusion, worsening dehydration, and hemodynamic instability.

The evidence underscores that in patients with multimorbidity, the risk of adverse drug reactions (ADRs) and drug-drug interactions (DDIs) is not simply additive but synergistic ^[2]. Common medications for heart failure (e.g., diuretics, ACE inhibitors) and diabetes (e.g., sulfonylureas, metformin) are frequently implicated in preventable ADRs. Diuretics can exacerbate dehydration and cause electrolyte imbalances that precipitate confusion. Metformin, primarily renally cleared, can accumulate in the setting of dehydration and declining kidney function, with a rare but serious risk of lactic acidosis. An ACE inhibitor, combined with dehydration, can precipitate acute kidney injury. Therefore, the most critical initial step is not to simply treat the symptoms (dehydration, confusion) but to identify and interrupt the underlying pathophysiological driver, which is highly likely to be medication-related toxicity from altered pharmacokinetics.

A structured, pharmacist-led medication reconciliation process has been shown to be effective in identifying potentially inappropriate medications (PIMs) and reducing regimen complexity, particularly in acute care settings where rapid decisions are made with incomplete histories ^[3]. The nurse, as the clinician at the bedside, is in a pivotal position to synthesize the assessment findings—poor oral intake, confusion, and a complex medication list—and initiate a collaborative intervention. Assessing kidney function (e.g., checking serum creatinine and BUN) provides the objective data needed to quantify the degree of renal impairment. Reviewing medication dosages with the healthcare provider or a clinical pharmacist directly applies this data to determine which drugs require dose adjustment, temporary withholding, or discontinuation. This action addresses the root cause of the physiological changes, making it the priority over supportive measures alone.