A 69-year-old man cannot take aspirin due to bronchospasm. What class of drug is most likely prescribed to inhibit platelet function?

• A. Inhibits prostaglandin synthesis
• B. Blocks serotonin release
• C. Activates adenosine deaminase
• D. Blocks the ADP receptors

Answer: (D)

The most appropriate choice for this patient's need to inhibit platelet function, especially given his intolerance to aspirin, involves the mechanism of blocking ADP receptors. This is because ADP serves as a key activator of the platelet aggregation pathway. Drugs that block ADP receptors, such as clopidogrel and ticagrelor, are utilized specifically to inhibit platelet activation and aggregation independent of the cyclooxygenase pathway, which is how aspirin exerts its effects.

In patients who have contraindications to aspirin, such as this individual who experiences bronchospasm, alternative antiplatelet medications that act through this mechanism can effectively prevent thrombus formation and reduce cardiovascular events without the risk of the respiratory side effects associated with aspirin. These ADP receptor antagonists are frequently prescribed in settings such as acute coronary syndrome or after stent placement, where platelet inhibition is critical.

The other options, such as those involving prostaglandin synthesis inhibition, serotonin release, or adenosine deaminase activation, do not directly correlate with the established clinical approach to achieving platelet inhibition in a patient with a history of aspirin intolerance.