What is a suitable alternative to aspirin for a patient with a documented aspirin allergy and a history of acute coronary syndrome?

Clopidogrel is a suitable alternative for a patient with a documented aspirin allergy and a history of acute coronary syndrome because it is an antiplatelet medication that works differently from aspirin. While aspirin is a cyclooxygenase inhibitor that prevents the formation of thromboxane A2, leading to decreased platelet aggregation, clopidogrel acts by irreversibly inhibiting the P2Y12 component of ADP receptors on the platelet surface, which also promotes platelet aggregation.

In patients with cardiovascular conditions such as acute coronary syndrome, clopidogrel provides effective antiplatelet therapy to reduce the risk of further cardiovascular events without the risk of an allergic reaction associated with aspirin.

The other options do have therapeutic roles but do not replace aspirin specifically in this context. Rivaroxaban and apixaban are direct oral anticoagulants primarily used for the prevention and treatment of thromboembolic events, such as in atrial fibrillation or deep vein thrombosis, and they do not fulfill the immediate need for an antiplatelet effect in acute coronary syndrome management. Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that can inhibit platelet function but is not indicated as an alternative antiplatelet therapy for