A patient with renal impairment is prescribed a medication that is primarily excreted by the kidneys. What adjustment should the nurse anticipate?

Choice A reason: CT scan with contrast is an order that the nurse should question for the client who is taking metformin for hyperglycemia. Metformin is a medication that lowers the blood glucose level by decreasing the hepatic glucose production and increasing the insulin sensitivity¹. Metformin can cause a rare but serious complication called lactic acidosis, which is a buildup of lactic acid in the blood that can cause symptoms such as weakness, nausea, vomiting, or breathing problems. CT scan with contrast involves injecting iodinated contrast material into the bloodstream, which can affect the kidney function and increase the risk of lactic acidosis in patients taking metformin. The nurse should consult with the prescriber and the pharmacist about the need to stop metformin before and after the CT scan with contrast, and to monitor the kidney function and the blood glucose level of the client.

Choice B reason: Chest X-ray 1 view is not an order that the nurse should question for the client who is taking metformin for hyperglycemia. Chest X-ray is a diagnostic test that uses a small amount of radiation to produce images of the lungs, heart, and chest wall. Chest X-ray does not involve any contrast material or affect the kidney function or the blood glucose level. The nurse should follow the standard precautions and procedures for performing a chest X-ray, such as verifying the client's identity, checking for pregnancy, removing any metal objects, and positioning the client properly.

Choice C reason: V/Q scan is not an order that the nurse should question for the client who is taking metformin for hyperglycemia. V/Q scan is a diagnostic test that measures the ventilation and perfusion of the lungs, and can detect any abnormalities such as pulmonary embolism or chronic obstructive pulmonary disease. V/Q scan involves injecting a radioactive tracer into the bloodstream and inhaling a radioactive gas, which are then detected by a special camera. V/Q scan does not affect the kidney function or the blood glucose level. The nurse should follow the standard precautions and procedures for performing a V/Q scan, such as verifying the client's identity, checking for allergies, explaining the procedure, and monitoring the vital signs.

Choice D reason: Bilateral lower extremity ultrasound is not an order that the nurse should question for the client who is taking metformin for hyperglycemia. Bilateral lower extremity ultrasound is a diagnostic test that uses sound waves to produce images of the blood vessels in the legs, and can detect any abnormalities such as deep vein thrombosis or peripheral arterial disease. Bilateral lower extremity ultrasound does not involve any contrast material or affect the kidney function or the blood glucose level. The nurse should follow the standard precautions and procedures for performing a bilateral lower extremity ultrasound, such as verifying the client's identity, explaining the procedure, and applying a gel and a probe to the legs.

Choice A reason: This is correct. The liver is the main organ responsible for drug metabolism. The enzymes that the body uses to metabolize drugs are present throughout the body but are most abundant in the liver. The liver can transform drugs into more polar and water-soluble compounds, which can then be excreted by the kidneys or the biliary system.

Choice B reason: This is incorrect. The lungs are not primarily responsible for drug metabolism, although they can play a minor role in some cases. The lungs can metabolize some drugs that are inhaled, such as anesthetics, or drugs that circulate through the pulmonary blood vessels, such as propranolol. However, the lungs have a lower capacity and a lower variety of enzymes than the liver.

Choice C reason: This is incorrect. The heart is not responsible for drug metabolism, although it can be affected by it. The heart is the organ that pumps blood throughout the body, delivering oxygen and nutrients to the tissues and organs. The heart can be influenced by the pharmacokinetics and pharmacodynamics of drugs, which are the processes of drug absorption, distribution, metabolism, and excretion, and the effects of drugs on the body, respectively.

Choice D reason: This is incorrect. The kidney is not primarily responsible for drug metabolism, although it is important for drug excretion. The kidney is the organ that filters the blood and removes waste products and excess fluid as urine. The kidney can excrete drugs that are water-soluble or that are not reabsorbed by the tubules. The kidney can also metabolize some drugs, such as aspirin, but to a lesser extent than the liver.