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Ticagrelor Dyspnoea — RACP Adult Medicine MCQ

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EasyClinical PharmacologyTicagrelor DyspnoeaRACP Adult Medicine

A 70-year-old man on ticagrelor after a recent ACS develops dyspnoea. His chest examination is clear, SpO₂ is 96%, and CXR is normal. BNP is not elevated. What is the most likely cause?

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Correct answer: APulmonary embolism

Ticagrelor causes dyspnoea in 10–15% of patients through adenosine-mediated mechanisms (ticagrelor inhibits cellular adenosine uptake, increasing adenosine levels which stimulate pulmonary vagal C-fibres). It is dose-related, usually mild, often self-limiting within the first week, and does NOT represent cardiopulmonary pathology. Investigation to exclude cardiac and pulmonary causes is appropriate. If dyspnoea is intolerable and genuine, switching to clopidogrel or prasugrel may be necessary. Dyspnoea is NOT a reason to discontinue antiplatelet therapy without assessment.

Reference: AMH – 2025 – Ticagrelor; NHF/CSANZ – 2025 – ACS Guideline