A nurse is providing teaching for a client who has a new prescription for rifampin. Which of the following statements should the nurse include?

Before administering the first dose of metformin, the nurse should evaluate the client's creatinine level. Metformin is primarily excreted by the kidneys, and its clearance from the body depends on the renal function. If the client has impaired kidney function, metformin can accumulate in the body and lead to potential adverse effects, particularly lactic acidosis.

Monitoring the creatinine level helps assess the client's kidney function and determines whether it is safe to administer metformin. If the creatinine level is elevated, indicating reduced kidney function, the nurse should consult with the healthcare provider to determine the appropriate dose adjustment or consider an alternative treatment option.

Let's go through the other options and explain why they are not the priority laboratory results to evaluate before administering metformin:

A. Potassium level: While monitoring potassium levels is important in some situations, it is not a primary concern before administering metformin. Metformin does not have a significant effect on potassium levels, and it is not a medication known for causing hypokalemia (low potassium levels).

C. Platelet count: Metformin does not have a direct impact on platelet count, and evaluating platelet count is not typically required before starting metformin therapy. Platelet count monitoring may be relevant for certain other medications or medical conditions, but it is not specific to metformin administration.

D. Liver enzymes: While it is essential to monitor liver function in clients on long-term metformin therapy, evaluating liver enzymes before the first dose of metformin is not the priority. Metformin is primarily cleared by the kidneys, and liver enzymes are not directly affected by its initial administration. However, ongoing monitoring of liver function may be necessary during long-term

When caring for a client receiving heparin by continuous IV infusion for the treatment of venous thrombosis, the nurse should monitor the client's aPTT (Activated Partial Thromboplastin Time) to titrate the heparin dose.

Heparin is an anticoagulant medication used to prevent and treat blood clots. The aPTT is a coagulation test that measures the time it takes for the blood to clot when a specific activator is added. Monitoring the aPTT is a standard method for assessing the anticoagulant effect of heparin and ensuring that the client's blood remains within the desired therapeutic range.

The therapeutic range for aPTT while on heparin therapy varies depending on the indication and the client's condition but is generally maintained at a level that prolongs the clotting time enough to prevent and treat thrombosis while avoiding excessive bleeding risk.

Let's go through the other options:

A. Platelet function assay: While monitoring platelet function is essential for assessing overall hemostasis and platelet function, it is not specifically used for titrating heparin doses. Platelet function assays are more commonly used to assess the function of platelets in the context of platelet disorders or antiplatelet medication therapy.

C. INR (International Normalized Ratio): The INR is used to monitor the effect of vitamin K antagonist anticoagulants, such as warfarin, and is not the appropriate test for monitoring heparin therapy.

D. Amylase: Amylase is an enzyme produced by the pancreas and salivary glands and is not relevant for monitoring heparin therapy. Elevated amylase levels are typically associated with pancreatitis and not related to heparin treatment.