A 58-year-old man with hypertension and diabetes presents to the emergency department with chest pain of 3 hours duration, diaphoresis, and dyspnea. ECG shows ST depression in leads II, III, aVF with T-wave inversion. Troponin I is elevated at 0.8 ng/mL (normal <0.04). He is hemodynamically stable. What is the drug of choice for immediate antiplatelet therapy in this patient with NSTEMI?

Explanation

## Antiplatelet Strategy in NSTEMI **Key Point:** In NSTEMI, dual antiplatelet therapy (DAPT) with aspirin plus a P2Y₁₂ inhibitor is the cornerstone of acute management. Per current ACC/AHA 2021 and ESC 2020 guidelines, **ticagrelor is the preferred P2Y₁₂ inhibitor** for NSTEMI patients unless contraindicated. ### P2Y₁₂ Inhibitor Selection in NSTEMI | Drug | Loading Dose | Maintenance | Onset | Key Advantage | Limitation | |------|--------------|-------------|-------|---------------|------------| | **Ticagrelor** | 180 mg | 90 mg BD (acute); 60 mg BD (long-term) | ~30 min | Rapid onset, active drug, superior mortality benefit (PLATO trial) | Higher bleeding risk, dyspnea, bradycardia | | **Prasugrel** | 60 mg | 10 mg daily (5 mg if <60 kg or >75 yrs) | ~30 min | Potent, rapid | Contraindicated in prior stroke/TIA; not recommended before coronary anatomy known | | **Clopidogrel** | 600 mg | 75 mg daily | 2–6 hours | Cost-effective | Slower onset, prodrug, variable response; reserved for when ticagrelor/prasugrel are contraindicated | **High-Yield:** According to ACC/AHA 2021 NSTEMI guidelines (Class I recommendation), **ticagrelor 180 mg loading dose** is the preferred P2Y₁₂ inhibitor in NSTEMI because: - Faster onset of action (active drug, no hepatic conversion required) - Superior efficacy demonstrated in the PLATO trial (reduced cardiovascular death, MI, stroke vs. clopidogrel) - Recommended regardless of revascularization strategy (invasive or conservative) - No contraindications in this patient (no prior stroke, no active bleeding) **Clinical Pearl:** The maintenance dose of ticagrelor in the acute ACS phase is **90 mg twice daily** for the first 12 months; the 60 mg twice daily dose is used for extended therapy beyond 12 months (PEGASUS-TIMI 54 trial). The option states 60 mg BD which reflects the extended maintenance dose, but the loading dose of 180 mg is correct for NSTEMI. **Warning:** Clopidogrel is now a **second-line** agent, reserved for patients who cannot tolerate ticagrelor or prasugrel, or in resource-limited settings. Aspirin monotherapy alone is inadequate; DAPT is mandatory. Prasugrel should not be administered before coronary anatomy is known in NSTEMI. ### Timing and Dosing 1. **Aspirin:** 325 mg (or 300 mg) loading dose, then 75–100 mg daily indefinitely 2. **Ticagrelor:** 180 mg loading dose immediately, then maintenance for ≥12 months post-ACS [cite: ACC/AHA 2021 NSTEMI Guidelines; Harrison's Principles of Internal Medicine 21e Ch 297; PLATO Trial, NEJM 2009]