A nurse is caring for a 45-year-old client with chronic hepatitis B who is receiving antiviral therapy with tenofovir. Which nursing intervention is the priority for this client?

Tenofovir therapy requires priority monitoring for renal and bone adverse effects due to its nephrotoxicity and bone demineralization risks. Other options are important but not specific priorities for this medication.

Priority Nursing Intervention for a Client on Tenofovir

When caring for a client with chronic hepatitis B receiving tenofovir, the nurse must prioritize monitoring for adverse effects that pose the most immediate and significant risk to long-term client safety. While all listed interventions have a place in holistic care, the unique toxicity profile of tenofovir disoproxil fumarate (TDF) makes one assessment the clear clinical priority.

Analysis of the Correct Answer

The correct intervention is to monitor for renal and bone-related adverse effects. This is the priority because long-term therapy with tenofovir, specifically the older formulation tenofovir disoproxil fumarate (TDF), is strongly associated with nephrotoxicity and reductions in bone mineral density. The foundational research underscores that "drug-related renal and bone toxicities remain a major clinical concern" during long-term nucleos(t)ide analogue therapy for chronic hepatitis B ^[1]. This safety signal is so significant that it has driven the development and clinical adoption of a newer formulation, tenofovir alafenamide (TAF), which has an improved safety profile for both the kidneys and bones ^[1]. As a nurse, your proactive monitoring through serial serum creatinine, estimated glomerular filtration rate (eGFR), serum phosphate levels, and urinalysis, along with a baseline and periodic bone density scans, is critical for early detection and prevention of irreversible damage. The clinical efficacy of tenofovir in suppressing HBV is exceptionally high, with one study demonstrating 100% viral suppression , but this powerful therapeutic benefit must be carefully balanced against its potential for harm.

Why the Other Options Are Not the Priority

- Option 2: Assess for signs of hepatic encephalopathy daily. While chronic hepatitis B can progress to cirrhosis and subsequently hepatic encephalopathy, this is a complication of advanced liver disease, not a direct adverse effect of the antiviral medication itself. A client stable on antiviral therapy is managed to prevent this progression. The immediate, drug-specific toxicities of tenofovir on the kidneys and bones represent a more direct and pressing safety issue for a client currently on treatment [1,2]. Daily assessment for encephalopathy is not a standard requirement for a stable client on oral antivirals without decompensated cirrhosis.

- Option 3: Administer the medication with high-fat meals. This instruction is incorrect for standard tenofovir disoproxil fumarate (TDF). In fact, TDF is typically administered without regard to meals. The instruction to take the medication with a high-fat meal applies to the newer formulation, tenofovir alafenamide (TAF), to enhance its absorption. Confusing the administration requirements of TDF and TAF could lead to suboptimal drug levels. The provided evidence does not support this as a standard intervention for all tenofovir formulations ^[1].

- Option 4: Encourage increased fluid intake to prevent dehydration. While maintaining adequate hydration is a component of general good health and can be supportive for renal function, it is not the priority intervention. The nephrotoxicity associated with TDF is related to proximal tubular dysfunction, not simply prerenal dehydration. Encouraging fluids is a supportive measure but does not replace the critical, specific nursing action of monitoring renal function through laboratory values to detect drug-induced tubular injury early ^[1].

Clinical Reasoning and Pathophysiology

The priority-setting framework here is based on the direct, well-documented adverse effect profile of the medication being administered. Tenofovir is primarily eliminated by the kidneys through a combination of glomerular filtration and active tubular secretion. The drug can accumulate in renal proximal tubular cells, causing mitochondrial toxicity, which manifests as proximal tubular dysfunction. This can lead to Fanconi syndrome, characterized by phosphate wasting, proteinuria, glycosuria, and ultimately a decline in eGFR. The bone toxicity is a direct consequence of this renal phosphate wasting, leading to osteomalacia and decreased bone mineral density. The research explicitly validates the need for this comparative safety monitoring between TAF and TDF, highlighting that the older formulation (TDF) carries a higher risk for these adverse events ^[1]. The high antiviral efficacy of tenofovir is not in question [3,4]; the nursing priority, therefore, shifts from efficacy to safety surveillance, making the detection of insidious renal and bone injury the most critical nursing function for a client on long-term therapy.