Acute Coronary Syndrome ; drug therapy ; Angioplasty, Balloon, Coronary ; Aspirin ; administration & dosage ; Humans ; Platelet Aggregation Inhibitors ; administration & dosage ; Thrombelastography ; Ticlopidine ; administration & dosage ; analogs & derivatives ; Tyrosine ; administration & dosage ; analogs & derivatives

Aggressive intravenous and oral dual antiplatelet therapy has established primary percutaneous coronary intervention (PCI) as the standard of care for acute myocardial infarction. Clopidogrel is currently the thienopyridine of choice for dual antiplatelet therapy in patients treated with PCI. The dose regime and duration of therapy of clopidogrel has undergone multiple refinements. Recently, 2 novel third generation oral inhibitors of P2Y12 receptors, prasugrel and ticagrelor, have undergone clinical evaluation with promising results. This article is a non-exhaustive review of the literature, concentrating on the role of current and novel oral antiplatelet agents for acute myocardial infarction particularly highlighting the limitations and issues associated with clopidogrel use.
Adenosine ; administration & dosage ; analogs & derivatives ; Angioplasty, Balloon, Coronary ; Drug Therapy, Combination ; Electrocardiography ; Humans ; Myocardial Infarction ; drug therapy ; surgery ; Piperazines ; administration & dosage ; Platelet Aggregation Inhibitors ; administration & dosage ; Prasugrel Hydrochloride ; Thiophenes ; administration & dosage ; Ticlopidine ; administration & dosage ; analogs & derivatives

BACKGROUNDThe combination of cilostazol, aspirin and clopidogrel (triple antiplatelet therapy, TAT) after a percutaneous coronary intervention has been used as an alternative therapy. We performed a meta-analysis to evaluate the efficacy and safety of TAT for patients after percutaneous coronary intervention (PCI).

METHODSWe systematically searched Pubmed, Embase and Web of Science databases to identify all randomized controlled trials (RCTs) that compared dual antiplatelet therapy (DAT) with and without cilostazol after PCI. All analyses were conducted using Review Manager 5.0.

RESULTSThe final analysis consisted of 4474 patients from ten studies. The combined results suggested that there was a lower risk of cardiac death (relative risk (RR) = 0.55, 95% confidence interval (CI): 0.31 - 0.98, P < 0.05) and major adverse cardiac events (MACEs) (RR = 0.63, 95% CI: 0.54 - 0.74, P < 0.05) in patients treated with TAT as compared to those with DAT follow-ups after six months to one year; no significant difference was observed in bleeding and non-fatal myocardial infarction (MI) (RR = 1.14, 95% CI: 0.80 - 1.64, P > 0.05; RR = 0.87, 95% CI: 0.42 - 1.83, P > 0.05). However, the rate of adverse drug reaction was higher in patients receiving TAT than in patients receiving DAT (RR = 2.21, 95% CI: 1.84 - 2.66, P < 0.05). Moreover, there was a lower risk of stent thrombosis in patients treated with TAT as compared to those treated with DAT (RR = 0.44, 95% CI: 0.21 - 0.94, P < 0.05). The TAT group had a reduced risk of target lesion revascularization (TLR) (RR = 0.60, 95% CI: 0.43 - 0.82, P = 0.001) and target vessel revascularization (TVR) than the DAT group (RR = 0.56, 95% CI: 0.45 - 0.71, P < 0.05). The number of MACEs was lower for patients in the TAT group than in the DAT group with diabetes mellitus sub-analysis (RR = 0.41, 95% CI: 0.28 - 0.61, P < 0.05). But no significant difference was observed between the two groups regarding MACEs in patients with drug-eluting stent implantations (RR = 0.82, 95% CI: 0.65 - 1.03, P > 0.05).

CONCLUSIONTAT could significantly reduce the rates of MACEs and cardiac death in comparison to DAT, but more attention should be paid to adverse side effects of the drugs.

Aspirin ; administration & dosage ; Drug Therapy, Combination ; Humans ; Percutaneous Coronary Intervention ; Platelet Aggregation Inhibitors ; administration & dosage ; adverse effects ; Publication Bias ; Stents ; adverse effects ; Tetrazoles ; administration & dosage ; Ticlopidine ; administration & dosage ; analogs & derivatives

The present study was designed to determine the effects of puerarin pre-treatment on the pharmacokinetics of the oral anticoagulant agent warfarin and the antiplatelet agent clopidogrel in rats. In the treatment group, rats was gavaged with warfarin or clopidogrel after repeated treatment with puerarin at intraperitoneal doses of 20, 60, or 200 mg·kg(-1) for 7 days, while rats in the control group were administrated only with the same dose warfarin or clopidogrel. Plasma samples were obtained at the prescribed times and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). The results showed that rats treated with puerarin at all the test doses of 20, 60 and 200 mg·kg(-1) were found to affect the pharmacokinetics of warfarin, but not clopidogrel, suggesting a potential herb-drug interaction between puerarin and warfarin.
Animals ; Anticoagulants ; pharmacokinetics ; Chromatography, Liquid ; Clopidogrel ; Drug Administration Schedule ; Herb-Drug Interactions ; Injections, Intraperitoneal ; Isoflavones ; administration & dosage ; pharmacology ; Male ; Platelet Aggregation Inhibitors ; pharmacokinetics ; Rats ; Rats, Wistar ; Tandem Mass Spectrometry ; Ticlopidine ; analogs & derivatives ; pharmacokinetics ; Vasodilator Agents ; administration & dosage ; pharmacology ; Warfarin ; pharmacokinetics

The combined use of batifiban, a synthetic platelet GPII b/ IIIa receptor antagonist, and antithrombin agents is an attractive option for the treatment of patients with non-ST-segment elevation (NSTE) acute coronary syndrome (ACS) and those scheduled for percutaneous coronary intervention. To observe whether antithrombin agents affect the pharmacokinetic and pharmacodynamic properties of batifiban in combination therapy and optimize clinical administration dosage of batifiban, an open-label and parallel study was conducted. Thirty healthy subjects were randomly divided into three groups, which were sequentially treated with batifiban alone, or oral coadministration of clopidogrel, aspirin and UFH, or batifiban coadministered with these antithrombin agents. Blood samples were collected at pre-specified time points. The evaluation index included the inhibition of platelet aggregation and pharmacokinetic parameters. The pharmacokinetic parameters of batifiban and batifiban coadministered with antithrombin agents showed no significant differences. The mean inhibition rate of platelet aggregation (%) suggested that neither batifiban alone nor antithrombin agents alone could provide such potent inhibition rate (>80%) to obtain the best clinical efficacy, but they had a synergistic effect on platelet inhibition. No serious adverse effects were observed. The results in these healthy subjects suggest that batifiban coadministrated with antithrombin agents could achieve optimum clinical treatment effect for patients with NSTE ACS, and also those scheduled for percutaneous coronary intervention.
Administration, Oral ; Adolescent ; Adult ; Area Under Curve ; Aspirin ; administration & dosage ; pharmacology ; China ; Drug Administration Schedule ; Female ; Fibrinolytic Agents ; administration & dosage ; pharmacology ; Heparin ; administration & dosage ; pharmacology ; Humans ; Infusions, Intravenous ; Injections, Intravenous ; Male ; Metabolic Clearance Rate ; drug effects ; Peptides, Cyclic ; administration & dosage ; pharmacokinetics ; Platelet Aggregation Inhibitors ; administration & dosage ; pharmacokinetics ; Ticlopidine ; administration & dosage ; analogs & derivatives ; pharmacology ; Time Factors ; Young Adult

This case report describes recurrent drug-eluting stent thrombosis with documented laboratory hyporesponsiveness to clopidogrel. The use of escalating doses of clopidogrel prevented subsequent episodes, but the patient developed gastrointestinal intolerance and diffuse cutaneous reaction, which resolved completely with prasugrel. Impressively, prasugrel 10 mg daily achieved an even lower vasodilator-stimulated phosphoprotein platelet reactivity index compared to clopidogrel 300 mg daily. Our case highlights the importance of alternative P2Y12 receptor antagonists for patients receiving drug-eluting stents.
Angioplasty, Balloon, Coronary ; Drug-Eluting Stents ; adverse effects ; Humans ; Male ; Middle Aged ; Myocardial Infarction ; therapy ; Piperazines ; therapeutic use ; Platelet Aggregation Inhibitors ; administration & dosage ; Prasugrel Hydrochloride ; Thiophenes ; therapeutic use ; Thrombosis ; drug therapy ; Ticlopidine ; administration & dosage ; analogs & derivatives ; Treatment Failure

BACKGROUNDRecurrent ischemic events occurred even during routine use of 75 mg clopidogrel in addition to aspirin, that indicated a potentially insufficient maintenance dosage of clopidogrel. The aim of the present study was to evaluate the short-term efficacy and safety of a 150 mg maintenance dose of clopidogrel following a 600 mg loading dose in patients with an acute coronary syndrome (ACS) undergoing drug eluting stent (DES) implantation.

METHODSBetween November 2005 and November 2006, a total of 813 consecutive ACS patients undergoing DES implantation were enrolled. A 600 mg loading dose was administered before percutaneous coronary intervention (PCI) and patients were randomized to receive clopidogrel 75 mg or 150 mg for 30 days in addition to 300 mg aspirin daily. Primary end points were the composite of cardiac death, non-fatal myocardial infarction (MI) and urgent target vessel revascularization (UTVR). Secondary end points included stent thrombosis (ST), major and minor bleeding events at 30 days.

RESULTSAt a follow-up period of 30 days, 4 (1.0%) patients in the 150 mg group and 9 (2.2%) patients in the 75 mg group (P > 0.05) reached the primary end points. There was no significant difference in the incidences of MI (0.5% vs 1.2%, P > 0.05), UTVR (0.7% vs 2.0%, P > 0.05), and cardiac death (0.2% vs 0.2%, P > 0.05) between the two groups. The incidence of ST (0 vs 1.5%, P < 0.05) was significantly lower in the 150 mg group than that in the 75 mg group. There were no significant differences between both groups regarding the risk of major (0.2% vs 0, P > 0.05) or minor (0.5% vs 0.2%, P > 0.05) bleedings.

CONCLUSIONA high clopidogrel maintenance dose of 150 mg daily following a 600 mg loading dose for the first month after PCI procedure reduces the risk of ST and appears to be safe in patients with ACS undergoing DES implantation.

Acute Coronary Syndrome ; therapy ; Aged ; Angioplasty, Balloon, Coronary ; methods ; Coronary Angiography ; Drug-Eluting Stents ; Female ; Humans ; Male ; Middle Aged ; Platelet Aggregation Inhibitors ; administration & dosage ; therapeutic use ; Ticlopidine ; administration & dosage ; analogs & derivatives ; therapeutic use ; Treatment Outcome

OBJECTIVETo investigate the effect of two clopidogrel pretreatment duration on platelet activation in patients undergoing stenting.

METHODSFrom July 2006 to December 2007 40 elective carotid or vertebral artery stenting patients were assigned into two groups: Group A (n = 24) initiated clopidogrel (75 mg/d) > or = 5 d before stenting; group B (n = 16) initiated 3 - 4 days. Platelet-monocyte aggregates and fibrinogen receptors analyzed by flow cytometric, and platelet aggregation tests using optical aggregometry, as well as serum soluble CD40 ligand quantified by enzyme-linked immunosorbent assay were assessed in peripheral blood samples obtained immediately before and at 0.5, 18 h and 6 d after stenting.

RESULTSPlatelet-monocyte aggregates, fibrinogen receptors and serum soluble CD40 ligand were higher in group B than in group A (14.59% vs 8.70%, P = 0.012; 4.87% vs 2.42%, P = 0.024; 5.79 microg/L vs 2.64 microg/L, P = 0.020) at 18 h after stenting. Serum soluble CD40 ligand was higher in group B than in group A (0.49 microg/L vs 0.31 microg/L, P = 0.033) at 0.5 h after stenting.

CONCLUSIONSPremedication before stenting with clopidogrel 75 mg/d merely 3 - 4 d may be insufficient to achieve adequate platelet inhibition, whereas clopidogrel initiated at least 5 d could obtain preferable clinical antiplatelet efficacy.

Adult ; Aged ; Aged, 80 and over ; Carotid Stenosis ; blood ; therapy ; Female ; Humans ; Male ; Middle Aged ; Platelet Activation ; drug effects ; Platelet Aggregation Inhibitors ; administration & dosage ; Stents ; Ticlopidine ; administration & dosage ; analogs & derivatives ; Time Factors

BACKGROUNDAspirin can inhibit inflammatory reactions and platelet aggregation, but little is known about the effects of the combination of aspirin plus clopidogrel, a new antiplatelet agent, on inflammation. The purpose of this study was to determine whether aspirin plus clopidogrel can further suppress inflammation in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS).

METHODSOne hundred and fifteen patients with NSTEACS were randomized into two groups: group A (aspirin alone, n =58) and group B (aspirin plus clopidogrel, n =57). Patients in group A received a loading dose of 300 mg aspirin, then 100 mg per day. The patients in group B received a loading dose of 300 mg aspirin and 300 mg clopidogrel, then 100 mg aspirin and 75 mg clopidogrel per day. Serum high sensitivity C-reactive protein (hs-CRP) and tumor necrosis factor-alpha (TNF-alpha) were measured in all patients at baseline prior to any drug treatment after admission, and at 7 and 30 days after beginning drug treatment. Thirty healthy volunteers on no medications were enrolled as controls (group C).

RESULTSBaseline levels of hs-CRP and TNF-alpha in group A and group B were significantly higher than those in group C. Seven days after administration, the levels of hs-CRP in both group A and group B decreased significantly [Group A: (6.15 +/- 1.39) mg/L vs (9.18 +/- 1.62) mg/L, P <0.01; Group B:(4.99 +/- 1.62) mg/L vs (10.29 +/- 1.47) mg/L, P <0.01]. Similarly, levels of TNF- alpha in both groups decreased at 7 days compared to baseline [Group A: (90.99 +/- 28.91) pg/ml vs (117.20 +/- 37.13) pg/ml, P <0.01; Group B: (74.32 +/- 21.83) pg/ml vs (115.27 +/- 32.11) pg/ml, P <0.01]. Thirty days after administration, the levels of hs-CRP in both group A and group B decreased further to (3.49 +/- 1.53) mg/L, and (2.40 +/- 1.17) mg/L respectively (P <0.01 for both comparisons). Levels of TNF-alpha in groups A and B also decreased significantly between 7 and 30 days, to 63.28 +/- 29.01 pg/ml (group A) and (43.95 +/- 17.10) pg/ml (group B; P <0.01 for both comparisons). Significantly lower levels of hs-CRP and TNF-alpha were observed in group B compared to Group A at thirty days after initiating drug treatment (P <0.05).

CONCLUSIONSAspirin plus clopidogrel treatment reduced levels of serum hs-CRP and TNF-alpha in patients with NSTEACS significantly more than aspirin alone. Because both aspirin and clopidogrel produce important anti-inflammatory effects, these results suggest the possibility that long-term treatment with aspirin plus clopidogrel may produce greater clinical benefits compared to treatment with aspirin alone.

Adult ; Aged ; Angina, Unstable ; blood ; physiopathology ; Aspirin ; administration & dosage ; C-Reactive Protein ; analysis ; Drug Therapy, Combination ; Electrocardiography ; Female ; Humans ; Inflammation ; drug therapy ; Male ; Middle Aged ; Myocardial Infarction ; blood ; physiopathology ; Ticlopidine ; administration & dosage ; analogs & derivatives ; Tumor Necrosis Factor-alpha ; analysis

BACKGROUNDAdenosine phosphate-mediated platelet aggregation is a prognostic factor for major adverse cardiac events in patients who have undergone selective percutaneous coronary interventions. This study aimed to assess whether an adjusted loading dose of clopidogrel could more effectively inhibit platelet aggregation in patients undergoing selected percutaneous coronary intervention.

METHODSA total of 205 patients undergoing selected percutaneous coronary intervention were enrolled in this multicenter, prospective, randomized study. Patients receiving domestic clopidogrel (n = 104) served as the Talcom (Taijia) group; others (n = 101) received Plavix, the Plavix group. Patients received up to 3 additional 300-mg loading doses of clopidogrel to decrease the adenosine phosphate-mediated platelet aggregation index by more than 50% (the primary endpoint) compared with the baseline. The secondary endpoint was major adverse cardiovascular events at 12 months.

RESULTSCompared with the rational loading dosage, the tailored loading dosage better inhibited platelet aggregation based on a > 50% decrease in adenosine phosphate-mediated platelet aggregation (rational loading dosage vs. tailored loading dosage, 48% vs. 73%, P = 0.028). There was no significant difference in the eligible index between the Talcom and Plavix groups (47% vs. 49% at 300 mg; 62% vs. 59% at 600 mg; 74% vs. 72% at 900 mg; P > 0.05) based on a standard adenosine diphosphate-mediated platelet aggregation decrease of > 50%. After 12 months of follow-up, there were no significant differences in major adverse cardiac events (2.5% vs. 2.9%, P = 5.43). No acute or subacute stent thrombosis events occurred.

CONCLUSIONAn adjusted loading dose of clopidogrel could have significant effects on antiplatelet aggregation compared with a rational dose, decreasing 1-year major adverse cardiac events in patients undergoing percutaneous coronary interventions based on adenosine phosphate-mediated platelet aggregation with no increase in bleeding.

Adenosine Diphosphate ; pharmacology ; Aged ; Angioplasty, Balloon, Coronary ; Female ; Humans ; Male ; Middle Aged ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; administration & dosage ; Prospective Studies ; Ticlopidine ; administration & dosage ; adverse effects ; analogs & derivatives