A nurse is providing teaching to a client who has a history of diabetes mellitus and a new prescription for hydrochlorothiazide to treat uncontrolled hypertension.
Which of the following information should the nurse include in the teaching?

Choice A rationale

A prothrombin time (PT) of 15.5 seconds, while slightly above the normal range of 11 to 12.5 seconds, indicates a mild prolongation of clotting time. For a client on warfarin, a slight elevation in PT is often expected as it reflects the anticoagulant effect. This value alone may not necessitate immediate reporting.

Choice B rationale

An activated partial thromboplastin time (aPTT) of 45 seconds, slightly above the normal range of 30 to 40 seconds, indicates a minor prolongation in the intrinsic and common pathways of coagulation. While relevant for heparin therapy, its direct significance for warfarin's primary monitoring is less critical.

Choice C rationale

An International Normalized Ratio (INR) of 5.2 is significantly elevated above the therapeutic range for most conditions, which is typically 2.0 to 3.0 for clients on warfarin. An INR of 5.2 indicates a high risk of bleeding complications due to excessive anticoagulation, requiring immediate provider notification. Normal range is 0.8 to 1.1.

Choice D rationale

A platelet count of 90,000/mcL is below the normal range of 150,000 to 400,000/mcL, indicating thrombocytopenia. While important for hemostasis, warfarin primarily affects clotting factors, not platelet production. However, a low platelet count combined with high INR further increases bleeding risk, necessitating reporting.

Choice A rationale

Blood glucose monitoring accuracy is generally not directly affected by hydrochlorothiazide. The medication's impact is on glucose metabolism itself, not the accuracy of the measurement device. Hydrochlorothiazide affects the pancreatic beta cells or peripheral insulin sensitivity, leading to altered glucose homeostasis, not erroneous readings from a glucometer.

Choice B rationale

Decreasing insulin dosage is generally not appropriate when taking hydrochlorothiazide. Hydrochlorothiazide, a thiazide diuretic, can induce hyperglycemia by impairing insulin secretion from the pancreatic beta cells or by reducing peripheral glucose utilization, thereby requiring an *increase* in insulin dosage to maintain glycemic control, not a decrease.

Choice C rationale

Hydrochlorothiazide therapy can elevate blood glucose levels in clients who have diabetes. This effect is attributed to the medication's ability to impair insulin secretion from pancreatic beta cells or to decrease peripheral glucose utilization, leading to insulin resistance. This necessitates careful blood glucose monitoring (normal fasting glucose <100 mg/dL).

Choice D rationale

Reducing sodium in the diet while taking hydrochlorothiazide is beneficial for blood pressure control by augmenting the diuretic's effects, but it does not directly control blood glucose levels. While a healthy diet supports overall health, the primary mechanism of glucose elevation from hydrochlorothiazide is metabolic, not sodium-related.