8 Clinical Trials for Various Conditions
Study to see if platelet transfusion stop or lessen the effect of the drug on platelets
Ticagrelor is an oral, reversibly-binding, direct-acting P2Y12 receptor antagonist used clinically for the prevention of atherothrombotic events in patients with acute coronary syndromes (ACS). Guideline recommendations on the use of dual antiplatelet therapy (DAPT) have been formulated that ticagrelor 90 mg twice daily plus aspirin in preference to clopidogrel 75mg daily plus aspirin for patients who have an ACS with or without ST-segment elevation. These recommendations are primarily based on large, randomized, Phase III clinical trials. However, few East Asian patients (or those of East Asian descent) have been included in these trials to assess the use of these drugs. In addition, a growing body of data supported that East Asian might have different adverse event profiles (thrombophilia and bleeding) and "therapeutic window" compared with white subjects. Furthermore, "East Asian paradox" phenomenon has been described that East Asian patients have a higher prevalence of platelet reactivity during DAPT, but an ischaemic event rate following PCI or ACS is similar or even lower than white patients. Therefore, the antiplatelet treatment strategy that is most appropriate for East Asian patients is increasingly urgent. Therefore, we performed the current study to observe the different effects of low-dose ticagrelor (45 mg twice daily), conventional-dose ticagrelor (90 mg twice daily) and clopidogrel (75mg once daily) on high platelet reactivity (HPR) and IPA, and investigated the safety and efficacy of low-dose ticagrelor further in Chinese patients with non-ST-elevation ACS (NSTE-ACS).
PICOLO is a double blind placebo controlled phase II dose ranging, dose escalating study in patients of Blalock-Taussig age categories (neonates and infants/toddlers), to determine the dose providing inhibition of platelet aggregation similar to adults.
This study will measure the percentage of platelet aggregation inhibition with a loading dose of clopidogrel (300 mg) using the VerifyNow Assay System in healthy volunteers who have drank 11 oz of grapefruit juice. It will also measure the percentage of platelet aggregation inhibition with a maintenance dose of clopidogrel (75 mg/day) using the VerifyNow Assay System in healthy volunteers who have drank 11 oz grapefruit juice daily.
With potent analgesic properties, perceived hemodynamic benefits and limited alternatives, opiates are the analgesic mainstay for acute coronary syndrome (ACS) patients reporting peri-procedural pain or nitrate-resistant chest pain. However, large observational studies suggest that opiate administration during ACS may result in adverse cardiovascular outcomes. Complimenting this, a number of recent mechanistic studies have demonstrated delayed and attenuated effects of oral dual anti-platelet therapy (DAPT) on platelet inhibition endpoints among subjects receiving intravenous morphine. These studies support the hypothesis that morphine delays the gastrointestinal absorption of DAPT medications. However, no data exist on the impact of intravenous fentanyl, a systemic opioid analgesic routinely administered during percutaneous coronary intervention (PCI) procedures, on the platelet inhibition effects of DAPT. The investigators hypothesize that, similar to morphine, fentanyl administered at the time of PCI will reduce and delay the effect of DAPT on platelet function. As such, the primary aim of this study is to test the impact of intravenous fentanyl on residual platelet reactivity by randomizing patients undergoing PCI to a strategy of peri-procedural benzodiazepine plus non-systemic local analgesia or to the current standard of benzodiazepine plus intravenous fentanyl. Given the critical need for rapid and robust inhibition of platelet function during PCI, this trial has true potential to change clinical practice, particularly if the investigators demonstrate reduced DAPT absorption and elevated residual platelet reactivity among patients receiving fentanyl during PCI.
The investigators aim to determine if patients with systolic heart failure treated with prasugrel achieve greater platelet inhibition compared to those treated with clopidogrel.
The objective of this study is to determine if the action of the drug called clopidogrel, that you will start taking, will be decreased by another drug called atorvastatin, that you will also start taking. Clopidogrel is an oral antiplatelet agent that has been shown to prevent strokes and heart attacks. Atorvastatin is a cholesterol lowering agent. Twenty adults 18-75 years of age requiring cholesterol-lowering agent and antiplatelet agent therapy will be recruited for this study during their cardiology clinic visitation. In one group, antiplatelet agent (clopidogrel) regimen will be administered first, then followed by cholesterol-lowering medication (atorvastatin). In the second group, atorvastatin will be administered first, followed by clopidogrel. A new test called the erythromycin breath test will be administered to you three times during the study to measure how your liver will metabolize these drugs. Blood samples will also be obtained to assess platelet function. The criteria for exclusion are patient refusal or inability to give written consent, patients with allergic reaction to erythromycin, patients with known bleeding problems, liver disease, significant lung disease kidney disease and pregnancy. Patients with psychiatric impairment and documented history of substance abuse will also be excluded from the study.
This study is to determine whether the AggreGuide platelet aggregometer can discern the effect of low dose aspirin on subjects platelet aggregation using arachidonic acid as the agonist.