A nurse teaches a patient who takes daily low-dose aspirin for protection against myocardial infarction and stroke to avoid also taking which medication?

Choice A reason: Diphenhydramine, an antihistamine, does not significantly interact with aspirin’s antiplatelet effects. It primarily blocks histamine receptors, affecting allergies, not platelet aggregation. While it may cause drowsiness, it doesn’t increase bleeding risk or counteract aspirin’s cardiovascular benefits, making it safe to use concurrently with low-dose aspirin. Choice B reason: Loratadine, a second-generation antihistamine, targets histamine receptors to relieve allergy symptoms. It has no known interaction with aspirin’s antiplatelet mechanism or bleeding risk. Its minimal side effect profile makes it compatible with low-dose aspirin for cardiovascular protection, so avoiding it is unnecessary in this context. Choice C reason: Ibuprofen, an NSAID, competes with aspirin for COX-1 binding sites, reducing aspirin’s antiplatelet effect critical for preventing myocardial infarction and stroke. It also increases gastrointestinal bleeding risk when combined with aspirin, making it contraindicated for patients on low-dose aspirin therapy, thus the correct choice to avoid. Choice D reason: Multivitamins do not interfere with aspirin’s antiplatelet action or increase bleeding risk. They provide supplemental nutrients without affecting COX-1 inhibition or platelet aggregation. There’s no pharmacological basis for avoiding multivitamins with low-dose aspirin, making this choice irrelevant for the patient’s cardiovascular regimen.