A nurse is reinforcing teaching with a client who has tuberculosis (TB) and a prescription for isoniazid. Which of the following instructions should the nurse include?

Choice A reason: This is the correct data, because blood glucose using a glucometer can help diagnose and monitor the client's condition, which is likely diabetic ketoacidosis (DKA). DKA is a serious complication of diabetes mellitus, characterized by high blood glucose, ketones in the urine, and acidosis in the blood. Fruity breath odor, dry mouth, and extreme thirst are common signs of DKA.

Choice B reason: This is an irrelevant data, because pupillary reaction to light has no relation to the client's condition, which is likely DKA. Pupillary reaction to light can help assess the client's neurological status and possible brain injury.

Choice C reason: This is an irrelevant data, because deep tendon reflexes have no relation to the client's condition, which is likely DKA. Deep tendon reflexes can help assess the client's neuromuscular function and possible spinal cord injury.

Choice D reason: This is a relevant data, but not the first one. Liver function laboratory values can help assess the client's hepatic function and possible liver damage, which can be a complication of DKA. However, blood glucose using a glucometer is more urgent and specific for the diagnosis and management of DKA.

Choice A reason: This is the correct finding, because rifampin is an antibiotic that can cause red-orange discoloration of urine, saliva, sweat, tears, and other body fluids. This is a harmless and expected adverse effect of rifampin, and does not indicate any damage to the kidneys or liver. The client should be informed about this effect and advised to wear soft contact lenses, as rifampin can stain them permanently.

Choice B reason: This is an incorrect finding, because increased ecchymosis, or bruising, is not a harmless or expected adverse effect of rifampin, but a sign of bleeding disorder or thrombocytopenia, which is a rare but serious complication of rifampin. Rifampin can interfere with the synthesis of vitamin K, which is essential for blood clotting, and cause bleeding problems. The client should report any signs of bleeding, such as ecchymosis, petechiae, hematuria, or epistaxis, to the provider.

Choice C reason: This is an incorrect finding, because yellow appearance of the sclerae, or jaundice, is not a harmless or expected adverse effect of rifampin, but a sign of liver damage or hepatitis, which is a rare but serious complication of rifampin. Rifampin can cause inflammation and injury to the liver cells, and impair the metabolism and excretion of bilirubin, which is a yellow pigment that accumulates in the skin and eyes when the liver is damaged. The client should report any signs of liver dysfunction, such as jaundice, dark urine, pale stools, or abdominal pain, to the provider.

Choice D reason: This is an incorrect finding, because lack of energy, or fatigue, is not a harmless or expected adverse effect of rifampin, but a sign of anemia or hypothyroidism, which are rare but serious complications of rifampin. Rifampin can cause hemolytic anemia, which is a condition that occurs when the red blood cells are destroyed faster than they are produced, and hypothyroidism, which is a condition that occurs when the thyroid gland produces insufficient thyroid hormone. The client should report any signs of anemia or hypothyroidism, such as fatigue, weakness, pallor, or cold intolerance, to the provider.