A 45-year-old woman presents with 1 hour of central crushing chest pain, sweating and nausea. ECG shows ST depression in leads V4-V6 and troponin is elevated. She is diagnosed with non-ST-elevation acute coronary syndrome (NSTEACS). In addition to antiplatelet therapy and anticoagulation, which medicine is recommended early for symptom control and prognosis in the absence of contraindications?