Does Pantoprazole Reduce the Anti-platelet Effect of Clopidogrel?

Study Overview
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Brief Summary
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The investigators sought to evaluate the influence of pantoprazole, indicated as less effective than other proton pump inhibitors, on the antiplatelet effect of clopidogrel, with stratification of the population according to the presence of cytochrome (CYP) 2C19 polymorphism.

Detailed Description
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Participants being treated with a maintenance dose of 75 mg clopidogrel and 100 mg aspirin daily after previous PCI with coronary stenting were included in the study. Participants were randomly assigned to either the pantoprazole 40 mg once-daily group or the ranitidine 150 mg twice-daily group using a computer-generated randomized table. An independent investigator generated the random allocation sequence. Blood samples were collected at 9:00 on day prior to treatment (day 0) and on day 9. Measuring impedance was performed by one independent investigator in a blinded manner.

Conditions
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Antiplatelet Effect

Intervention / Treatment
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* Drug: Pantoprazole
* Drug: Ranitidine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients being treated with a maintenance dose of 75 mg clopidogrel and 100 mg aspirin daily after previous PCI with coronary stenting were included in the study. All patients received standardized therapy with a loading dose of 600 mg of clopidogrel hydrogen sulfate and 400 mg aspirin. All participants had a normal platelet count (150,000-450,000/mL). Exclusion Criteria: Patients with severe liver disorders, current gastrointestinal disorders, a current infection, congestive heart failure, or a known bleeding disorder as well as patients on bivalirudin or glycoprotein IIb/III antagonists within the last 7 days were excluded from the study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 79 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Pantoprazole<br>Drug: Pantoprazole 40 mg once-daily | Drug: Pantoprazole<br>* pantoprazole 40 mg once-daily<br>|
| Experimental: Ranitidine<br>Drug: Ranitidine 150 mg twice-daily | Drug: Ranitidine<br>* ranitidine 150 mg twice-daily<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants with more than 5 Ω of impedance after intervention by an aggregometer which measures platelet aggregation in whole blood samples | 8 days after administration of pantoprazole (or ranitidine) | 8 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of the impedance value (Ω) by an aggregometer which measures platelet aggregation in whole blood samples | 8 days after administration of pantoprazole (or ranitidine) | baseline and 8days | 
| Number of participants with gastrointestinal bleeding |  | up to 2weeks | 
| Number of participants with reccured coronary artery disease |  | up to 2weeks |