Antiplatelet Therapy and Adverse Effects

Introduction to Antiplatelet Agents and Side Effects

The American Heart Association guidelines list common side effects of clopidogrel, including dizziness, fatigue, stomach upset or pain, bruising, bleeding, and diarrhea, but do not specifically mention shortness of breath, although evidence suggests an association between clopidogrel and respiratory symptoms, with ticagrelor causing dyspnea in approximately 10-15% of patients 1, 2

The mechanism of respiratory symptoms with clopidogrel is not fully understood, but ticagrelor's effect on dyspnea is thought to be related to inhibition of adenosine reuptake by erythrocytes, increased circulating levels of adenosine, and adenosine-induced effects on respiration 1

When a patient on clopidogrel reports shortness of breath or dizziness, evaluate the severity and timing of symptoms in relation to medication initiation, and rule out other causes of dyspnea or dizziness, such as cardiac or pulmonary causes, orthostatic hypotension, inner ear disorders, and drug interactions 1, 2
Based on severity and clinical context, mild symptoms may be managed with reassurance and continued monitoring, moderate symptoms may be managed by taking medication at bedtime, and severe or persistent symptoms may require consultation with the prescribing physician about alternative antiplatelet options 1, 2

If adverse effects are intolerable, alternative antiplatelet agents may be considered, including aspirin (81-325 mg daily), aspirin plus extended-release dipyridamole, or ticagrelor, although each has different efficacy and side effect profiles 2, 3, 4, 5, 6
The American College of Chest Physicians guidelines mention vertigo as a side effect of other antiplatelet agents that share similar mechanisms to clopidogrel, and the American Heart Association's 2013 scientific statement on thrombosis in pediatric and congenital heart disease explicitly lists vertigo as a potential side effect of clopidogrel 2, 7
In patients with specific conditions, such as Fabry disease, management of adverse effects may require additional considerations, such as anti-nausea medications for severe episodes of vertigo with dizziness and nausea 8