The nurse administers atenolol 50 mg PO bid to a client who has coronary artery disease. The nurse understands that the therapeutic effect of this medication for this client is to:

Choice A reason: The client had an allergic reaction to losartan, a drug that belongs to the class of angiotensin II receptor blockers (ARBs). ¹ Anaphylaxis is a severe and potentially life-threatening allergic reaction that can cause swelling of the lips, tongue, throat, and face, as well as difficulty breathing, low blood pressure, and shock. ² The client needs immediate medical attention and treatment with oxygen, fluids, and epinephrine. ³

Choice B reason: The client did not have an expected side effect of the medication. Losartan is used to treat high blood pressure and heart failure by blocking the action of angiotensin II, a hormone that causes blood vessels to constrict and retain salt and water. ¹ Some common side effects of losartan include dizziness, headache, fatigue, cough, and nausea. ⁴ Anaphylaxis is not a common or expected side effect of losartan, but a rare and serious adverse reaction.

Choice C reason: The client should not have a prescription change to enalapril. Enalapril is another drug that lowers blood pressure and heart failure, but it belongs to the class of angiotensin-converting enzyme (ACE) inhibitors. ⁵ ACE inhibitors and ARBs have similar mechanisms of action and effects, but they differ in how they block the angiotensin system. However, both classes of drugs can cause allergic reactions and anaphylaxis in some people, especially those who have a history of allergy to either drug. The client should avoid both ACE inhibitors and ARBs and use another type of blood pressure medication.

Choice D reason: The client should not avoid taking the medication with food. Food does not affect the absorption or effectiveness of losartan. ⁴ The client can take the medication with or without food, as directed by the provider. However, the client should avoid grapefruit and grapefruit juice, as they can interact with losartan and increase the risk of side effects.

Choice A reason: The Schilling test is not used to diagnose G6PD anemia, which is a genetic disorder that causes red blood cells to break down when exposed to certain substances. The Schilling test is used to measure how well the body absorbs vitamin B12 from the intestine. ¹²

Choice B reason: The Schilling test does not require the patient to be NPO (nothing by mouth) for 12 hours prior to the test. The patient can drink water, but should avoid food for 8 hours before the test. ²

Choice C reason: The Schilling test is a 24-hour urine specimen collection test. The patient is given a dose of radioactive vitamin B12 by mouth and another dose of nonradioactive vitamin B12 by injection. The urine is collected for 24 hours to measure how much of the radioactive vitamin B12 is excreted. This indicates how well the body absorbs vitamin B12 from the intestine. ¹²

Choice D reason: The Schilling test does not entail administration of methylcellulose prior to the test. Methylcellulose is a type of laxative that can interfere with the absorption of vitamin B12. The patient should avoid taking any laxatives, antacids, or antibiotics before the test. ²³