Which has better evidence, Clopidogrel (Plavix) or Acetylsalicylic acid (Aspirin)?

From the Guidelines

Plavix (clopidogrel) has a better evidence base compared to aspirin for reducing major adverse cardiovascular events in patients with established cardiovascular disease, particularly in those with acute coronary syndrome or those undergoing percutaneous coronary intervention (PCI). The CAPRIE trial, which compared clopidogrel to aspirin in patients at risk for ischemic events, found that clopidogrel reduced the relative risk of myocardial infarction, ischemic stroke, or vascular death by 8.7% compared to aspirin 1. Additionally, the CURE trial demonstrated that the combination of clopidogrel and aspirin reduced the risk of cardiovascular death, nonfatal myocardial infarction, or stroke by 20% compared to aspirin alone in patients with acute coronary syndrome without ST-segment elevation 1.

Some key points to consider when choosing between Plavix and aspirin include:

• The specific condition being treated: Plavix may be more effective for secondary prevention after heart attack, stroke, or in patients with established cardiovascular disease, while aspirin may be more suitable for primary prevention in people without established cardiovascular disease.
• The potential for drug interactions and monitoring requirements: Plavix may have more potential drug interactions and require more monitoring than aspirin.
• The cost of the medication: Plavix is generally more expensive than aspirin.
• The use of dual antiplatelet therapy (DAPT): Many patients benefit from combining Plavix and aspirin for a limited time (typically 6-12 months) after coronary stenting or acute coronary syndrome, followed by single antiplatelet therapy.

It's also important to note that the European Society of Cardiology recommends clopidogrel as an alternative to aspirin for high-risk patients with coronary, cerebrovascular, or peripheral arterial disease who have a contraindication to low-dose aspirin 1. However, the size of any additional benefit of clopidogrel over aspirin is statistically uncertain, and clopidogrel has not been granted a claim of superiority over aspirin by regulatory authorities 1.

In terms of dosing, typical dosing for Plavix is 75mg daily, while aspirin is usually prescribed at 81-325mg daily. A loading dose of 300mg clopidogrel may be used in patients with acute coronary syndromes without ST-segment elevation, followed by 75mg daily 1.

Overall, the choice between Plavix and aspirin should be based on individual patient factors and the specific clinical scenario, taking into account the potential benefits and risks of each medication.

From the FDA Drug Label

The CAPRIE trial was a 19,185-patient, 304-center, international, randomized, double-blind, parallel-group study comparing clopidogrel (75 mg daily) to aspirin (325 mg daily) The overall relative risk reduction (9. 8% vs 10.6%) was 8.7%, p=0.045. The statistical significance favoring clopidogrel over aspirin was marginal (p=0. 045).

The evidence suggests that clopidogrel (Plavix) has a slightly better effect than aspirin in reducing the incidence of outcome events, primarily myocardial infarction, with a relative risk reduction of 8.7% (p=0.045) 2.

• The benefit of clopidogrel over aspirin was most apparent in patients with peripheral arterial disease.
• However, in patients with recent myocardial infarction, clopidogrel was not numerically superior to aspirin.

From the Research

Comparison of Plavix and Aspirin

• Plavix (clopidogrel) and aspirin are both antiplatelet medications used to prevent blood clots in patients with cardiovascular disease 3.
• In primary prevention, there is little evidence of benefit of any antiplatelet therapy, including Plavix and aspirin, and such therapy carries the risk of excess bleeding 3.
• In secondary prevention, stable patients benefit from long-term antiplatelet monotherapy, with aspirin being the first choice in those with coronary heart disease and clopidogrel in those with cerebrovascular disease 3.

Efficacy and Safety

• The use of clopidogrel plus proton-pump inhibitors (PPIs) provides gastrointestinal benefits, but is associated with an increased cardiovascular risk among patients with a history of gastrointestinal bleeding 4.
• PPIs may reduce the cardiovascular protection by aspirin and clopidogrel, although the antiplatelet effect of the new P2Y12 receptor antagonists, ticagrelor and prasugrel, seems less influenced by PPI co-treatment 5.
• Proton-pump inhibitors reduce gastrointestinal events regardless of aspirin dose in patients requiring dual antiplatelet therapy, including those taking clopidogrel 6.

Clinical Use

• Clopidogrel is often used as part of dual antiplatelet therapy (DAPT) for the secondary prevention of acute coronary syndrome (ACS), in combination with aspirin 7.
• Deescalation of DAPT by switching from prasugrel or ticagrelor to clopidogrel may be required in some patients with ACS, due to the increased risk of bleeding associated with the newer P2Y12 inhibitors 7.
• Clopidogrel monotherapy may be used in patients with symptomatic peripheral artery disease (PAD) or very high-risk transient ischemic attack (TIA) or stroke 7.