Management of Coronary Artery Disease and Chronic Stable Angina

Yesenia Camero, PharmD, BCPS; Jinwi Ghogomu, PharmD, BCPS, CPh

Disclosures

US Pharmacist. 2017;42(2):27-31. 

In This Article

Medications to Prevent Myocardial Infarction and Death

Antiplatelet Therapy

Platelets and their byproducts play an important role in the incidence of occlusive vascular events, including myocardial infarction (MI). When these platelet-rich atherosclerotic plaques become disrupted, platelet aggregation ensues and ultimately leads to formation of a thrombus, which may precipitate a CVE.[7]

Aspirin is an antiplatelet agent that works through irreversible inhibition of cyclooxygenase, leading to decreased formation of the prostaglandin derivative thromboxane A2 and to inhibited platelet aggregation. Aspirin has been associated with a 37% reduction in the risk of serious CVEs, as well as a 46% decrease in the risk of unstable angina and a 53% decrease in the need for coronary angioplasty.[7] Therefore, it is important that the patient be treated with aspirin 75 to 162 mg daily unless a contraindication exists. Doses of 75 to 162 mg are comparable to doses of 325 mg, but are associated with a lower risk of bleeding.

Clopidogrel (Plavix) is considered an acceptable alternative for patients who cannot tolerate aspirin. Clopidogrel is a thienopyridine derivative that inhibits platelet aggregation through selective and irreversible inhibition of the adenosine diphosphate P2Y12 receptor. In one study, clopidogrel 75 mg daily demonstrated superiority over aspirin 325 mg daily, although the degree of clinical benefit was small.[8] Because no other studies have been conducted comparing the two agents in this patient population, clopidogrel is considered an alternative to aspirin.

Prasugrel (Effient), another thienopyridine antiplatelet agent, has more potent antiplatelet effects and less interpatient variability in response compared with clopidogrel, but it has an increased risk of bleeding in patients undergoing percutaneous coronary intervention (PCI). Prasugrel is not currently indicated for patients with SIHD without ACS.[9] The newest P2Y12 inhibitor, ticagrelor (Brilinta), is also indicated only for patients with ACS.[10]

Dipyramidole, which is commonly prescribed in combination with aspirin (as Aggrenox) in patients with ischemic stroke, also possesses antiplatelet effects, but it does not have an established role in patients with SIHD. Moreover, because dipyridamole vasodilates coronary resistance vessels and can provoke exercise-induced myocardial ischemia, it is not recommended for secondary prevention in patients with SIHD.[6]

Dual antiplatelet therapy (DAPT) with aspirin and clopidogrel can provide additional benefits and may reduce CVEs and mortality in certain high-risk SIHD patients. It is well established that patients with a recent MI who have undergone PCI with stent placement require DAPT for up to 1 year. DAPT is not recommended in patients with SIHD without prior stent implantation and no history of ACS or MI.[11] Decisions about treatment with, and duration of, DAPT in SIHD patients who have a history of MI or coronary stent implantation require a careful assessment of the benefits versus risks and a consideration of patient preference.

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