Clopidogrel: new preparation. An alternative to aspirin

(1) Clopidogrel, an antiplatelet drug chemically similar to ticlopidine, is marketed in France for secondary prevention of thrombotic complications in patients with a history of myocardial infarction, ischaemic stroke or peripheral arterial disease. (2) Marketing authorisation was based mainly on the CAPRIE trial, a study that involved 19,815 patients. In this trial of secondary cardiovascular prevention, clopidogrel was slightly more effective than aspirin (325 mg/day) according to a statistical analysis of a combined end point (ischaemic stroke, or myocardial infarction, or death of vascular causes). The difference was more marked in the subgroup of patients with obstructive arterial disease of the lower limbs. (3) Clopidogrel was well tolerated in this trial. The only adverse effects more frequent on clopidogrel than on aspirin were rash and diarrhoea. (4) Clopidogrel showed no haematological toxicity, an adverse effect that restricts the use of ticlopidine. (5) The lack of long-term follow-up in real clinical settings prevents any meaningful estimation of the safety profile or of the risk of drug interactions.     

Clopidogrel: a review of its use in the prevention of atherothrombosis

Clopidogrel is an ADP receptor antagonist that is indicated for the reduction of atherosclerotic events including myocardial infarction, ischaemic stroke and vascular death in patients with atherosclerosis manifested by recent stroke, myocardial infarction or established peripheral vascular disease. In the 19 185 patients enrolled in the multicentre, randomised double-blind CAPRIE study, the annual risk of the combined end-point of ischaemic stroke, myocardial infarction and death from vascular disease (vascular death) was significantly lower during treatment with clopidogrel 75 mg/day than aspirin 325 mg/day [5.3 vs 5.8%/year, respectively; relative risk reduction (RRR) 8.7%, p = 0.043] after a mean follow-up of 1.9 years. Clopidogrel provided even greater reductions in the risk of recurrent ischaemic events than aspirin in patients with a history of coronary artery bypass surgery, diabetes mellitus and in those receiving concomitant lipid-lowering therapy. Moreover there was a significant reduction in the incidence of hospitalisation in patients treated with clopidogrel. In a patient population (Saskatchewan, Canada) with a greater risk of ischaemic events than the CAPRIE study population, the number of patients needed to be treated with clopidogrel to prevent 1 ischaemic event was estimated to be 70 (vs 200 in the CAPRIE study). In randomised trials and registry surveys, clopidogrel 75 mg/day plus aspirin had similar efficacy (as measured by adverse cardiac outcomes) to ticlopidine 250mg twice daily plus aspirin during the 30 days after placement of intracoronary stents. Tolerability of clopidogrel was significantly better than ticlopidine in the randomised, double-blind CLASSICS study. Among patients treated with clopidogrel or aspirin in the CAPRIE study, the overall gastrointestinal tolerability of clopidogrel was generally better than that of aspirin; the frequency of gastrointestinal haemorrhage was significantly lower among patients treated with clopidogrel than aspirin. Diarrhoea, rash and pruritis were significantly more common with clopidogrel than aspirin. CONCLUSION: Clopidogrel was significantly more effective than aspirin in the prevention of vascular events (ischaemic stroke, myocardial infarction or vascular death) [corrected] in patients with atherothrombotic disease manifested by recent myocardial infarction, recent ischaemic stroke or symptomatic peripheral arterial occlusive disease [corrected] in the CAPRIE study. The overall tolerability profile of the drug was similar to that of aspirin, although gastrointestinal haemorrhage occurred significantly less often in clopidogrel recipients. The drug is widely used in combination with aspirin for the prevention of atherothrombosis after placement of intravascular stents, and available data suggest that this combination is as effective as ticlopidine plus aspirin for this indication.     

Antiplatelet therapy in peripheral arterial disease

Antiplatelet therapy significantly reduces the incidence of vascular death, nonfatal myocardial infarction, and nonfatal stroke in patients with peripheral arterial disease (PAD) and intermittent claudication, in patients undergoing peripheral grafting, in patients undergoing peripheral angioplasty, and in patients with carotid disease. Aspirin, aspirin plus dipyridamole, ticlodipine, and clopidogrel have been shown to be efficacious in the treatment of PAD. Data from the Clopidogrel versus Aspirin in Patients at Risk for Ischaemic Events (CAPRIE) trial demonstrated in 11,592 patients with PAD that patients randomized to clopidogrel 75 mg daily had a 24% significant (p=0.0028) reduction in vascular death, nonfatal myocardial infarction, and nonfatal stroke than patients randomized to aspirin 325 mg daily. These data favor the use of clopidogrel in patients with PAD.     

Clopidogrel: a CURE in acute coronary syndromes?

The standard approach to preventing acute coronary syndromes (ACSs)has been to inhibit platelet aggregation with aspirin and to inhibit blood coagulation with low molecular-weight heparin (LMWH). Even with this combination there is still a substantial short and long-term cardiovascular risk. The Clopidogrel in Unstable angina to prevent Recurrent Events (CURE) trial [1] compared clopidogrel plus aspirin against aspirin alone in patients with ACSs. The clopidogrel regimen was a loading dose of 300 mg p.o. followed by 75 mg/day and the recommended dose of aspirin was 75 - 325 mg/day. The first primary outcome was a composite of death from cardiovascular causes, non-fatal myocardial infarction (MI) or stroke and this occurred significantly less often in the clopidogrel than the placebo group (9.3 vs. 11.4%). Although there were more clopidogrel patients with life-threatening bleeding (clopidogrel 2.2%, placebo 1.8%), this represented GI haemorrhages and bleeding at sites of arterial puncture rather than fatal bleeding. This trial suggests a role for clopidogrel in the long-term treatment of ACSs.     

CLARITY about the use of clopidogrel in patients with acute coronary syndromes and myocardial infarction

Clopidogrel was shown to have added benefits to aspirin in patients with acute coronary syndromes without ST-segment elevation in the Clopidogrel in Unstable Angina to Prevent Recurrent Events (CURE) trial. The cost in CURE was estimated to be US$442 greater in the clopidogrel group and the incremental cost-effectiveness ratio (incremental cost/life-year gained) was US$6318. Clopidogrel has also recently been shown to have added benefits to aspirin in patients with myocardial infarction with ST-segment elevation in the Clopidogrel as Adjunctive Reperfusion Therapy (CLARITY) – Thrombolysis in Myocardial Infarction (TIMI) 28 study. The primary efficacy composite end point in CLARITY was an occluded infarct-related artery, death from any cause prior to angiography, or recurrent myocardial infarction, and this end point occurred less in the clopidogrel group (15%, 262 of 1752 patients) than placebo group (21.7%, 377 of 1739 patients). This difference was predominantly due to a reduction in the occluded infarct-related artery, which occurred in less of the clopidogrel (11.7%) than placebo group (18.4%). There was also a reduction in urgent revascularisations in the clopidogrel group of CLARITY. Thus, clopidogrel is effective and cost effective in acute coronary syndromes, and is also beneficial in patients with myocardial infarction with ST-segment elevation.     

CLARITY about the use of clopidogrel in patients with acute coronary syndromes and myocardial infarction

Clopidogrel was shown to have added benefits to aspirin in patients with acute coronary syndromes without ST-segment elevation in the Clopidogrel in Unstable Angina to Prevent Recurrent Events (CURE) trial. The cost in CURE was estimated to be US442 dollars greater in the clopidogrel group and the incremental cost-effectiveness ratio (incremental cost/life-year gained) was US6318 dollars. Clopidogrel has also recently been shown to have added benefits to aspirin in patients with myocardial infarction with ST-segment elevation in the Clopidogrel as Adjunctive Reperfusion Therapy (CLARITY)--Thrombolysis in Myocardial Infarction (TIMI) 28 study. The primary efficacy composite end point in CLARITY was an occluded infarct-related artery, death from any cause prior to angiography, or recurrent myocardial infarction, and this end point occurred less in the clopidogrel group (15%, 262 of 1752 patients) than placebo group (21.7%, 377 of 1739 patients). This difference was predominantly due to a reduction in the occluded infarct-related artery, which occurred in less of the clopidogrel (11.7%) than placebo group (18.4%). There was also a reduction in urgent revascularisations in the clopidogrel group of CLARITY. Thus, clopidogrel is effective and cost effective in acute coronary syndromes, and is also beneficial in patients with myocardial infarction with ST-segment elevation.     

Clopidogrel

? Clopidogrel is a selective inhibitor of ADP-induced platelet aggregation.

? A large, multicenter, randomized study in 12562 patients with acute coronary syndromes without ST-segment elevation demonstrated that treatment with clopidogrel (loading dose of 300mg followed by once daily treatment with 75mg) in addition to standard therapy including aspirin (75 to 325 mg/day) significantly reduced the risk of the combined endpoint of cardiovascular death, myocardial infarction or stroke compared with treatment with standard therapy. Furthermore, the composite risk of these outcomes or refractory ischemia was also significantly reduced in patients treated with clopidogrel plus aspirin. The effects of clopidogrel were independent of background treatment with cardiovascular medications and/or interventions.

? The risk of severe ischemia, recurrent angina or heart failure was also significantly reduced in patients receiving clopidogrel plus aspirin. There was also a significant reduction in the need for coronary revascularization during the initial period of hospitalization.

? In patients undergoing percutaneous coronary intervention (PCI), the relative risk of the combined endpoint of cardiovascular death, myocardial infarction or urgent target-vessel revascularization within 30 days of the intervention was significantly reduced. Moreover, the relative risk of the single endpoint of myocardial infarction within 30 days of PCI was significantly in favor of clopidogrel-treated patients.

? Hemorrhagic events (both major and minor) were significantly more frequent in patients with acute coronary syndromes receiving treatment with clopidogrel plus aspirin than in patients treated with aspirin alone. This was largely attributable to an increased incidence in the rate of gastrointestinal hemorrhage and bleeding at the site of arterial puncture. However, there was no difference between the two groups in the incidence of bleeding episodes that were considered to be life-threatening.

     

Clopidogrel in ST-elevation myocardial infarction patients undergoing percutaneous coronary intervention

Clopidogrel has become a mainstay in the management of acute coronary syndrome patients over the past decade, as well as an essential component of percutaneous coronary intervention (PCI) pharmacotherapy. Until recently, no prospective study has evaluated the effectiveness of clopidogrel in the setting of an ST-segment elevation myocardial infarction (STEMI). The majority of patients presenting with STEMI receive thrombolytic therapy (aspirin, heparin and a fibrinolytic agent) although many do not achieve or maintain adequate reperfusion of the infarct-related artery. The CLARITY (Clopidogrel as Adjunctive Reperfusion Therapy) study and the PCI-CLARITY substudy were designed to address whether a beneficial effect of clopidogrel, including a loading dose, would be attained among STEMI patients who were being treated with thrombolytic therapy and undergoing coronary angiography during the index hospitalisation. A total of 3491 patients who presented within 12 h after the onset of STEMI were randomly assigned to receive clopidogrel (300-mg loading dose followed by 75 mg daily) or placebo. Patients were scheduled to undergo coronary angiography after 48 h, and those who underwent PCI during the index hospitalisation formed the basis of PCI-CLARITY. This PCI cohort was followed for the combined end point of cardiovascular death, recurrent myocardial infarction and stroke for 30 days.     

Mesalazine for the treatment of inflammatory bowel disease

Clopidogrel has become a mainstay in the management of acute coronary syndrome patients over the past decade, as well as an essential component of percutaneous coronary intervention (PCI) pharmacotherapy. Until recently, no prospective study has evaluated the effectiveness of clopidogrel in the setting of an ST-segment elevation myocardial infarction (STEMI). The majority of patients presenting with STEMI receive thrombolytic therapy (aspirin, heparin and a fibrinolytic agent) although many do not achieve or maintain adequate reperfusion of the infarct-related artery. The CLARITY (Clopidogrel as Adjunctive Reperfusion Therapy) study and the PCI–CLARITY substudy were designed to address whether a beneficial effect of clopidogrel, including a loading dose, would be attained among STEMI patients who were being treated with thrombolytic therapy and undergoing coronary angiography during the index hospitalisation. A total of 3491 patients who presented within 12 h after the onset of STEMI were randomly assigned to receive clopidogrel (300-mg loading dose followed by 75 mg daily) or placebo. Patients were scheduled to undergo coronary angiography after 48 h, and those who underwent PCI during the index hospitalisation formed the basis of PCI–CLARITY. This PCI cohort was followed for the combined end point of cardiovascular death, recurrent myocardial infarction and stroke for 30 days.     

Combination antiplatelet agents for secondary prevention of ischemic stroke

Stroke is a leading cause of death and the primary cause of serious, long-term disability in the United States. Joint guidelines from the American Heart Association (AHA) and American Stroke Association (ASA), as well as recent guidelines from the Eighth American College of Chest Physicians (ACCP) Conference on Antithrombotic and Antiplatelet Therapy, recommend aspirin, clopidogrel, or extended-release dipyridamole plus aspirin as acceptable first-line options for secondary prevention of ischemic events in patients with a history of ischemic stroke or transient ischemic attack (TIA). The ACCP strongly recommends the combination of extended-release dipyridamole plus aspirin over aspirin monotherapy (highest level of evidence) and suggests clopidogrel monotherapy over aspirin monotherapy (lower level of evidence). The AHA-ASA guidelines suggest that either extended-release dipyridamole plus aspirin or clopidogrel monotherapy should be used over aspirin monotherapy. Both guidelines recommend avoiding the combination of clopidogrel and aspirin for most patients with previous stroke or TIA. Results from recent trials evaluating combination antiplatelet therapy have been published that enhance the AHA-ASA recommendations and provide the foundation for the updated ACCP guideline. To identify pertinent combination antiplatelet trials, a MEDLINE search of the literature from 1967-2007 was performed. Two trials were identified--the European-Australasian Stroke Prevention in Reversible Ischemia Trial (ESPRIT) and Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA). The ESPRIT compared aspirin monotherapy with the combination of aspirin plus extended-release dipyridamole for prevention of secondary ischemic events in patients with a history of TIA or minor stroke. The CHARISMA trial compared aspirin plus clopidogrel with aspirin alone in a population at high risk for atherothrombotic events using the composite outcome of myocardial infarction, stroke, and death from cardiovascular causes. Data from ESPRIT add to evidence that the combination of aspirin plus extended-release dipyridamole is superior to aspirin alone. The findings of the CHARISMA trial reinforce recommendations from both AHA-ASA and ACCP that the combination of aspirin and clopidogrel be reserved for special populations requiring this antiplatelet combination (e.g., those who have had coronary artery stenting).     

Incremental Effect of Clopidogrel on Important Outcomes in Patients with Cardiovascular Disease

OBJECTIVES: To quantify the impact of clopidogrel plus aspirin on the individual outcomes of death, myocardial infarction, or stroke in patients with established cardiovascular disease, or in patients with multiple risk factors for vascular disease. BACKGROUND: Randomized trials have demonstrated a reduction in composite outcomes when clopidogrel is added to aspirin therapy in patients with coronary artery disease; however, the magnitude of benefit on individual outcomes is unknown. METHODS: We conducted a meta-analysis on randomized, controlled trials that compared aspirin plus clopidogrel with aspirin plus placebo for the treatment of coronary artery disease. RESULTS: This analysis included five randomized trials (CURE, CREDO, CLARITY, COMMIT, and CHARISMA) in 79 624 patients. The incidence of all-cause mortality was 6.3% in the aspirin plus clopidogrel group versus 6.7% in the aspirin group (odds ratio [OR] 0.94; 95% CI 0.89, 0.99; p = 0.026). The incidence of myocardial infarction was 2.7% and 3.3% (OR 0.82; 95% CI 0.75, 0.89; p < 0.0001), and stroke was 1.2% and 1.4% (OR 0.82; 95% CI 0.73, 0.93; p = 0.002). Similarly, the incidence of major bleeding was 1.6% and 1.3% (OR 1.26; 95% CI 1.11, 1.41; p < 0.0001), and fatal bleeding was 0.28% and 0.27% (OR 1.04; 95% CI 0.76, 1.43; p = 0.79). CONCLUSION: The addition of clopidogrel to aspirin results in a small reduction in all-cause mortality in patients with ST-elevation myocardial infarction and a modest reduction in myocardial infarction and stroke in patients with cardiovascular disease. The overall incidence of major bleeding however is increased, although there is no excess of fatal bleeds or hemorrhagic strokes.     

Clopidogrel: a pharmacoeconomic review of its use in patients with non-ST elevation acute coronary syndromes

Clopidogrel (Plavix) is a selective inhibitor of adenosine diphosphate-induced platelet aggregation. In patients with acute coronary syndromes (ACS) [unstable angina or non-ST-segment elevation myocardial infarction], clopidogrel plus aspirin (acetylsalicylic acid) for up to 1 year significantly reduced the risk of cardiovascular events relative to placebo plus aspirin in the well designed clinical trial CURE (Clopidogrel in Unstable angina to prevent Recurrent Events) and its substudy in patients undergoing percutaneous coronary intervention (PCI) [PCI-CURE]. In pharmacoeconomic evaluations based on data from these trials conducted in a number of countries that used a variety of models, methods and/or type of costs, clopidogrel plus aspirin was consistently predicted to be cost effective relative to aspirin alone in the management of patients with ACS, including those undergoing PCI. Clopidogrel plus aspirin in patients with ACS reduced the incremental cost per cardiovascular event prevented and/or life-year gained (LYG) relative to aspirin alone in analyses using within-trial data (including longer-term analyses incorporating life-expectancy estimates) from the CURE or PCI-CURE studies. In Markov models of cost effectiveness with a lifetime horizon from a healthcare payer perspective based on the CURE trial, relative to aspirin alone, clopidogrel plus aspirin for 1 year was predicted to have incremental costs per LYG of 8132Euro in Spain (2003 values) and 1365Euro in Sweden (2000 values). In similar Swedish analyses from a healthcare payer perspective, clopidogrel plus aspirin for 1 year was predicted to have incremental costs per LYG of 10,993Euro (2004 values) relative to aspirin alone based on data from the PCI-CURE substudy. Broadly similar results have also been reported in modelled analyses from other countries. Cost-utility analyses based on the CURE trial suggest that, relative to lifelong aspirin alone, clopidogrel plus aspirin for 1 year followed by aspirin alone is associated with incremental costs per QALY gained that are below the traditional threshold of cost utility in Spain, the UK and the US. In patients with ACS, including those undergoing PCI, the addition of clopidogrel to standard therapy with aspirin is clinically effective in preventing cardiovascular events. Available pharmacoeconomic data from several countries, despite some inherent limitations, support the use of clopidogrel plus aspirin for up to 1 year as a cost-effective treatment relative to aspirin alone in this patient population.     

Prevention of coronary heart disease with aspirin and clopidogrel: efficacy, safety, costs and cost-effectiveness

Atherothrombotic coronary artery disease is the single most common cause of death worldwide and a growing public health problem. Platelets play a central role in the pathogenesis of atherothrombosis and are therefore commonly targeted by one or more antiplatelet drugs as part of primary and secondary atherothrombosis prevention strategies. Aspirin reduces the risk of serious vascular events (myocardial infarction, stroke or cardiovascular death) by approximately 20% in a broad range of high-risk patients and remains the first-line antiplatelet drug because of its relative safety, low cost and cost-effectiveness. Compared with aspirin alone, clopidogrel reduces the risk of serious vascular events by approximately 10% and the combination of aspirin and clopidogrel reduces the risk by approximately 20% in patients with non-ST-segment elevation acute coronary syndrome. Clopidogrel has a similar safety profile to aspirin but clopidogrel tablets are substantially more expensive. However, the incremental cost-effectiveness ratio of clopidogrel compared with aspirin is favourable, particularly in high-risk patients and is intermediate compared with a range of other effective therapeutic strategies for the treatment of coronary heart disease. Clopidogrel should be considered as a replacement for aspirin in patients who are allergic to aspirin, cannot tolerate aspirin, have experienced a recurrent atherothrombotic vascular event whilst taking aspirin and are at very high absolute risk of a serious vascular event (e.g., > 20%/year). The combination of clopidogrel and aspirin should be considered in patients with non-ST-segment elevation acute coronary syndrome or undergoing percutaneous coronary intervention.     

Clopidogrel and [symbol: see text] ticlopidine--improvements on aspirin?

Clopidogrel (Plavix-Sanofi Winthrop/Bristol-Myers Squibb) and [symbol: see text] ticlopidine (Ticlid-Sanofi Winthrop) are inhibitors of platelet function and are promoted as potential alternatives to aspirin. Clopidogrel is licensed for the secondary prevention of vascular events in patients with established atherosclerotic disease. The manufacturer claims that clopidogrel is "significantly more effective at reducing myocardial infarction, stroke and vascular death" compared to aspirin. Ticlopidine is licensed as an alternative to aspirin for secondary prevention of stroke and coronary complications in patients with intermittent claudication. However, in the UK, ticlopidine is more commonly used with aspirin to prevent complications following insertion of coronary stents during angioplasty. We consider whether the claims for clopidogrel and the current use of ticlopidine are justified.     

Antiplatelet drugs in cardiovascular prevention: coronary events: acute phase and secondary prevention

(1) Aspirin reduces acute-phase mortality after myocardial infarction, and also reduces the risk of myocardial infarction and death in patients with unstable angina. Aspirin reduces the risk of myocardial infarction in patients with stable angina and after unstable angina, and the risk of relapse after myocardial infarction. It reduces the risk of complications during coronary angioplasty, and the risk of venous coronary bypass graft occlusion after coronary surgery. (2) The best risk-benefit ratio with aspirin is achieved at a daily dose of 75-350 mg; 160 mg/day is the best-validated dose in the acute phase of myocardial infarction. (3) Aspirin must be combined with a thrombolytic agent in patients with myocardial infarction, and with heparin in patients with unstable angina. During coronary stenting the aspirin + clopidogrel combination may have a better risk-benefit ratio than the aspirin + ticlopidine combination. (4) Clopidogrel can be used when aspirin is contraindicated or poorly tolerated. (5) Oral anticoagulants seem a better option than aspirin after complicated myocardial infarction.     

Clinical pharmacokinetics of antiplatelet agents used in the secondary prevention of stroke

Stroke is one of the leading causes of death and debilitation. Several million stroke survivors are alive throughout the world today. Prevention of recurrent stroke is of major importance to stroke survivors. Several pharmacological agents are currently available for use in secondary stroke prevention.Clopidogrel, the combination of immediate-release aspirin and extended-release dipyridamole and aspirin alone are the most widely recommended agents for use in the secondary prevention of strokes. Clopidogrel has shown superiority over aspirin in the combined endpoints of stroke, death and myocardial infarction. The immediate-release aspirin/extended-release dipyridamole combination has shown superiority to aspirin alone in the secondary prevention of stroke.Dipyridamole has been studied as an antiplatelet agent for several decades. Early trials to prove its efficacy compared with aspirin were not favourable, and patients often experienced many adverse effects. Researchers began developing an extended-release formulation in an effort to maintain therapeutic blood concentrations with less frequent daily administration and better adverse effect profile. Pharmacokinetic analysis of this new product showed it to have a more consistent and reproducible absorption compared with immediate-release dipyridamole. The rate of absorption of extended-release dipyridamole is considerably slower than that of immediate-release dipyridamole, while similar plasma concentrations are maintained to optimise antiplatelet efficacy. This allows extended-release dipyridamole to be administered twice daily rather than four times daily.A large-scale randomised trial was conducted with extended-release dipyridamole 200mg in combination with immediate-release aspirin 25mg given twice daily. The combination product showed a greater efficacy at preventing a recurring stroke then either agent administered alone. Indirect comparisons with clopidogrel show that the combination of immediate-release aspirin/extended-release dipyridamole may be more effective than clopidogrel at preventing a recurring stroke.     

波立维联合阿司匹林肠溶片治疗非ST段抬高型心肌梗死的疗效观察

目的观察硫酸氯吡格雷(波立维)联合阿司匹林肠溶片治疗非ST段抬高型心肌梗死(NSTEMI)的临床疗效。方法 NSTEMI患者180例随机分为观察组和对照组各90例。对照组在常规治疗基础上给予波立维治疗;观察组在对照组治疗基础上加服阿司匹林肠溶片。2组疗程均为8周。观察比较2组的临床疗效和心脏不良事件。结果观察组总有效率为94.4%高于对照组的81.1%,心脏不良事件发生率为0低于对照组的7.8%,差异均有统计学意义(P<0.05)。结论波立维联合阿死匹林肠溶片治疗NSTEMI,临床效果显著,不良反应小,安全可靠。     

The association of clopidogrel and 2-oxo-clopidogrel plasma levels and the 40 months clinical outcome after primary PCI

Background A significant number of ischemic events occur even when adhering to dual antiplatelet therapy including aspirin and clopidogrel. Objectives The aim of our study was to determine predictors of long-term patient clinical outcome, among variables such as prodrug clopidogrel and intermediary metabolite 2-oxoclopidogrel concentrations, as well as patients’ clinical characteristics. Setting Department for the Treatment of Acute Coronary Syndrome in tertiary teaching hospital, Serbia. Methods This study enrolled 88 consecutive patients with first STEMI, treated with primary PCI, within 6 h of the chest pain onset and followed them 40 months. On the third day of hospitalization, blood samples were collected from each patient to measure clopidogrel and its metabolite 2-oxo-clopidogrel concentration by UHPLC-DAD-MS method. Main outcome measure Mortality from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke or hospitalization for urgent myocardial revascularization or heart failure. Results The composite clinical outcome of cardiovascular mortality, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for urgent myocardial revascularization or heart failure, was registered in 31 patients (35.2%) during the 40-month follow-up. Lower clopidogrel (p?<?0.05) and dose-adjusted clopidogrel concentrations (p?<?0.05) were associated with the higher incidence of composite outcome events. Their low plasma concentrations may be predicted by fentanyl administration (p?<?0.001) and creatinine clearance (p?<?0.01). The decrease in dose-adjusted clopidogrel unit for each ng/ml/mg increases the risk 21.7 times (p?<?0.05). Conclusion Clopidogrel dose-adjusted plasma concentration in STEMI patients, as well as multivessel coronary artery disease, showed significance in predicting an unfavorable composite clinical outcome after 40-month follow-up.     

Contemporary issues in clopidogrel therapy: new evidence shaping clinical practice

Antiplatelet therapy is a cornerstone in the management of acute coronary syndromes. Clopidogrel produces irreversible inhibition of the platelet adenosine diphosphate receptor, thereby attenuating activation and aggregation of platelets. Clopidogrel has been shown to prevent stent thrombosis in patients undergoing percutaneous coronary intervention (PCI) and reduces major adverse cardiovascular events in patients with unstable angina or non-ST-segment elevation myocardial infarction (non-STEMI). Recent studies have left clinicians with many questions regarding the role and dosing regimens of clopidogrel in STEMI, PCI, and primary or secondary prevention. Based on an analysis of the data, clopidogrel should be given in addition to aspirin and fibrinolytic therapy to patients with STEMI. In patients undergoing PCI, a loading dose of clopidogrel 600 mg should be given if the procedure needs to be performed within 15 hours of initial presentation. If PCI can be delayed for 15 hours or more, a loading dose of 300 mg can be used. Evidence also suggests that clopidogrel should not be prescribed for primary prevention in high-risk patients.