A nurse is caring for a client who is receiving warfarin (Coumadin) therapy to prevent a deep vein thrombosis.
Which of the following medications should the nurse have available in the event of an overdose?

Choice A rationale

Polyuria is defined as excessive or abnormally large production or passage of urine, often greater than 2.5 liters in a 24-hour period. It is typically associated with conditions like diabetes mellitus (osmotic diuresis) or diabetes insipidus (deficiency of antidiuretic hormone). A routine urinary tract infection (UTI) usually presents with symptoms like increased frequency and urgency, but not necessarily an increase in total urine volume.

Choice B rationale

Urinary frequency is a classic symptom of a urinary tract infection (UTI), particularly cystitis (bladder infection). Inflammation and irritation of the bladder lining (urothelium) caused by the colonizing bacteria (often E. coli) lead to increased sensitivity and involuntary detrusor muscle contractions, resulting in a persistent, urgent, and frequent need to void small amounts of urine.

Choice C rationale

Dysuria, or painful and difficult urination, is a hallmark clinical manifestation of a urinary tract infection (UTI). The discomfort arises from the inflammatory response in the urethra and bladder lining (mucosa) as the body attempts to fight the bacterial invasion, causing a burning sensation, especially upon the passage of acidic urine over the inflamed tissues.

Choice D rationale

Dependent edema is the accumulation of excess interstitial fluid in the body's lower extremities due to the effect of gravity, often associated with systemic conditions like heart failure (elevated venous pressure) or renal disease (proteinuria/hypoalbuminemia). It is not a typical or expected finding directly associated with an uncomplicated, localized urinary tract infection (UTI).

Choice E rationale

Hematuria, the presence of blood in the urine, is a common finding in urinary tract infections (UTIs), especially cystitis. Inflammation and damage to the delicate capillary walls and mucosal lining of the bladder and lower urinary tract by the invading bacteria (e.g., E. coli) and the host's immune response can lead to the leakage of red blood cells into the urine.

Choice A rationale

Enoxaparin (a low-molecular-weight heparin) and warfarin (a vitamin K antagonist) are anticoagulants that prevent the formation of new fibrin clots or the enlargement of existing ones, but they do not dissolve established clots; that is the function of thrombolytic agents like tissue plasminogen activator. Administering both aims for adequate anticoagulation until warfarin is fully effective. The correct response emphasizes discontinuing enoxaparin when warfarin is therapeutic.

Choice B rationale

Warfarin, an oral anticoagulant, inhibits vitamin K-dependent clotting factors (II, VII, IX, X), requiring several days to reach a therapeutic effect, which is monitored by the International Normalized Ratio (INR) (therapeutic range typically 2.0–3.0). Enoxaparin, an injectable anticoagulant with immediate onset, is continued concurrently to maintain protection until the INR is therapeutic and adequate anticoagulation is achieved via warfarin alone, a process called bridging.

Choice C rationale

Enoxaparin and warfarin have distinct mechanisms of action and do not enhance each other's effects synergistically; rather, they inhibit different points in the coagulation cascade. Enoxaparin mainly inhibits Factor Xa, while warfarin inhibits Vitamin K-dependent clotting factor synthesis. They are used together to provide immediate anticoagulation (enoxaparin) while awaiting warfarin's delayed onset.

Choice D rationale

While patient education is crucial, responding by deferring the client's question is not therapeutic and does not address the client's need for understanding their therapy. The nurse should explain the rationale for concurrent therapy (bridging) and the planned discontinuation of the injectable drug once the oral medication is within its therapeutic range.