A nurse is teaching a client who takes warfarin daily. Which of the following statements by the client indicates a need for further teaching?

Choice A reason: Client report of a headache is not the nurse's priority to report to the provider. A headache is a common and mild side effect of vancomycin, which is an antibiotic used to treat serious infections. A headache may be caused by dehydration, stress, or other factors, and can be relieved by drinking fluids, resting, or taking analgesics.

Choice B reason: Audible inspiratory stridor is the nurse's priority to report to the provider. Stridor is a high-pitched, wheezing sound that occurs when breathing in, and indicates a narrowing or obstruction of the airway. Stridor may be a sign of a severe allergic reaction, or anaphylaxis, to vancomycin, which can be life-threatening. Anaphylaxis can also cause swelling of the face, lips, tongue, or throat, difficulty breathing, low blood pressure, and shock. The nurse should stop the infusion, administer epinephrine, and monitor the client's vital signs.

Choice C reason: Client report of tinnitus is not the nurse's priority to report to the provider. Tinnitus is a ringing or buzzing sound in the ears, and may be a rare and serious side effect of vancomycin. Tinnitus may indicate damage to the inner ear, or ototoxicity, which can lead to hearing loss. The nurse should check the client's hearing and report any changes to the provider. The provider may adjust the dose or frequency of vancomycin, or switch to another antibiotic.

Choice D reason: Localized redness at the catheter insertion site is not the nurse's priority to report to the provider. Redness at the catheter insertion site may indicate irritation, inflammation, or infection of the skin or vein, and may be caused by the needle, the catheter, or the medication. The nurse should inspect the site, clean it with antiseptic, and apply a sterile dressing. The nurse should also monitor the site for signs of phlebitis, such as pain, swelling, warmth, or pus. The nurse may need to change the catheter or the infusion site if the redness persists or worsens.

Choice A reason: Taking the medication in the morning is not the correct instruction. Simvastatin is a statin drug that lowers cholesterol levels by inhibiting the enzyme that produces cholesterol in the liver. The liver produces more cholesterol at night, so simvastatin is more effective when taken in the evening or at bedtime.

Choice B reason: Avoiding grapefruit juice is the correct instruction. Grapefruit juice can increase the blood levels of simvastatin and cause serious side effects such as muscle damage, liver damage, and kidney failure. Grapefruit juice inhibits the enzyme that metabolizes simvastatin in the intestine, leading to higher concentrations of the drug in the bloodstream.

Choice C reason: Monitoring for ringing in the ears is not the correct instruction. Ringing in the ears, or tinnitus, is not a common or serious side effect of simvastatin. However, some other medications that lower cholesterol, such as niacin and gemfibrozil, can cause tinnitus. The client should report any unusual or persistent symptoms to the prescriber.

Choice D reason: Expecting brown-colored urine is not the correct instruction. Brown-colored urine, or hematuria, is not a normal or expected side effect of simvastatin. However, it may indicate a serious condition such as rhabdomyolysis, which is a rare but life-threatening complication of statin therapy. Rhabdomyolysis is the breakdown of muscle tissue that releases a protein called myoglobin into the bloodstream. Myoglobin can damage the kidneys and cause brown-colored urine. The client should seek immediate medical attention if they notice any signs of rhabdomyolysis, such as muscle pain, weakness, fever, or dark urine.