A nurse is caring for a client who has a new prescription for a nitroglycerin transdermal patch. Which of the following actions should the nurse take?

D. The INR is the standard laboratory test used to monitor the effectiveness of warfarin therapy. Warfarin interferes with the synthesis of vitamin K-dependent clotting factors, primarily factors II, VII, IX, and X. The INR provides a standardized measure of coagulation status, allowing healthcare providers to adjust warfarin dosage to maintain therapeutic anticoagulation while minimizing the risk of bleeding or thrombosis.
A. Platelets are involved in the process of blood clotting, but checking platelet levels is not specific to monitoring warfarin therapy. Platelet count may be relevant in assessing overall coagulation status, but it is not the primary laboratory value monitored for warfarin therapy.
B. OPTT measures the time it takes for blood to clot after specific clotting factors are activated. While OPTT is used to monitor the effectiveness of heparin therapy, it is not routinely monitored for warfarin therapy. Warfarin primarily affects the extrinsic pathway of the coagulation cascade, and the international normalized ratio (INR) is the standard laboratory test used to monitor warfarin therapy.
C. White blood cell count assesses the number of white blood cells in the blood and is used to evaluate the immune system and detect infections. Monitoring white blood cell count is not specific to warfarin therapy and is not routinely checked prior to administering warfarin.

A. Renal function typically declines with age, leading to a decrease in glomerular filtration rate (GFR) and renal blood flow. As a result, medications may be excreted more slowly from the body, leading to an increased risk of drug accumulation and potential toxicity. Adjustments in medication dosages or dosing intervals may be necessary to account for this age-related change.
B. Brain receptors do not change significantly. However, older adults may require lower doses to achieve the same therapeutic effect due to reduced receptor sensitivity.
C. Gastric emptying tends to slow down with age rather than increase. Delayed gastric emptying can affect the absorption of orally administered medications, leading to unpredictable drug levels and potentially reduced efficacy.
D. Hepatic function generally decreases with age, leading to a decline in the metabolic capacity of the liver. This can result in slower drug metabolism and clearance, prolonging the duration of action of medications and increasing the risk of adverse effects.