A patient is prescribed Flexeril (cyclobenzaprine) for muscle spasms. Which of the following is the most common side effect that the nurse should educate the patient about?

Choice A reason: Vasoconstriction is the desired therapeutic effect of phenylephrine in this context. Phenylephrine is a medication that stimulates the alpha1 receptors on the blood vessels, causing them to constrict or narrow. This increases the resistance to blood flow and raises the blood pressure. Phenylephrine is used as a vasopressor to treat hypotension, which is a condition of low blood pressure that can cause dizziness, fainting, or organ damage. The nurse should monitor the blood pressure and the peripheral pulses of the patient after administering phenylephrine.

Choice B reason: Bronchodilation is not the desired therapeutic effect of phenylephrine in this context. Phenylephrine is a medication that stimulates the alpha1 receptors on the blood vessels, causing them to constrict or narrow. It has no effect on the beta2 receptors on the bronchial smooth muscle, which are responsible for bronchodilation or widening of the airways. Phenylephrine is not used to treat respiratory conditions, such as asthma or chronic obstructive pulmonary disease, that cause bronchoconstriction or narrowing of the airways. The nurse should assess the respiratory rate and the breath sounds of the patient after administering phenylephrine.

Choice C reason: Diuresis is not the desired therapeutic effect of phenylephrine in this context. Phenylephrine is a medication that stimulates the alpha1 receptors on the blood vessels, causing them to constrict or narrow. It has no effect on the kidney function or the urine output. Phenylephrine is not used to treat fluid retention or edema, which are conditions of excess fluid in the body that can cause swelling, weight gain, or heart failure. The nurse should measure the urine output and the specific gravity of the patient after administering phenylephrine.

Choice D reason: Decreased heart rate is not the desired therapeutic effect of phenylephrine in this context. Phenylephrine is a medication that stimulates the alpha1 receptors on the blood vessels, causing them to constrict or narrow. It has little or no effect on the beta1 receptors on the heart, which are responsible for increasing the heart rate and the contractility. Phenylephrine may actually cause a reflex bradycardia, which is a slow heart rate that occurs when the baroreceptors in the blood vessels sense an increase in blood pressure and send signals to the brain to lower the heart rate. Phenylephrine is not used to treat tachycardia, which is a fast heart rate that can cause palpitations, chest pain, or arrhythmias. The nurse should monitor the electrocardiogram and the heart rate of the patient after administering phenylephrine.

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.