保栓通 Clopidogrel (Plavix): Review & Analysis
There is no evidence to support the use of Plavix at a lower dose or frequency.
Plavix Review & Analysis
(Sanofi-Aventis)
Generic name:
Clopidogrel bisulfate
Other names:
Plavix, Clopivas, Clopilet, Zyllt
What is this medication?
A blood thinning medicine
Class:
antiplatelet drugs
Mechanism of action:
adenosine diphosphate (ADP) inhibitor (The drug works by covalently and irreversibly binding to the P2Y12 receptor, the major receptor involved in ADP-induced aggregation of platelets).
Intake forms:
Oral
Dosage:
- 75, 300 mg tablets
- 75 mg once daily
Can it be cut in half?
Yes
Dose adjustments:
- Hepatic dosing: No dosage adjustment is necessary in patients with hepatic impairment.
- Renal dosing: In moderate to severe renal impairment caution is advised.
Indication:
For patients with non-ST-segment elevation ACS [unstable angina (UA)/non-ST-elevation myocardial infarction (NSTEMI)] including patients who are to be managed medically and those who are to be managed with coronary revascularization.
- Patients with ST-elevation myocardial infarction (STEMI).
- Recent myocardial infarction (MI), recent stroke, or established peripheral arterial disease.
Recent news:
- The FDA approved generic versions of Plavix® on May 17, 2012.
- Certain genetic factors and some medicines such as Prilosec (omeprazole) or Nexium (esomeprazole) reduce the effect of Plavix® leaving you at greater risk for heart attack and stroke.
- The U.S. Food and Drug Administration (FDA) added a Boxed Warning to the label for Plavix®, the anti-blood clotting medication. The Boxed Warning is for patients who do not effectively metabolize the drug (i.e. “poor metabolizers”) and therefore may not receive the full benefits of the drug [03-12-2010].
Thumbs up:
- Plavix® can be taken once daily with or without food.
- No dosage adjustment is necessary in patients with liver or kidney function impairment (in moderate to severe case caution is advised).
Thumbs down:
- The effectiveness of Plavix® depends on its activation to an active metabolite by the cytochrome P450.
- Reduced effectiveness in impaired CYP2C19 function: Avoid concomitant use with omeprazole or esomeprazole.
- Thrombotic Thrombocytopenic Purpura (TTP): TTP has been reported with Plavix®, including fatal cases.
Major adverse reactions:
- Bleeding, TTP, hepatitis, pancreatitis, angioedema, neutropenia (low number of white blood cells), diarrhea, cough, headache, dizziness, palpitations, UTI
Other warning and precautions:
- Taking Plavix® alone or with some other medicines, including aspirin other Non-steroidal anti-inflammatory drugs (NSAIDs) and warfarin may increase bleeding risk which can potentially be life-threatening.
Some worthwhile information:
- Plavix® increases risk of bleeding. Discontinue 5 days prior to elective surgery.
- Premature discontinuation increases risk of cardiovascular events.
- Platelet inhibition by Plavix® is irreversible and will last for the life of the platelet.
Review:
This medication has saved many patients’ life since its approval. It has clearly optimized the platelet inhibition and was essential in the treatment of the patients with acute coronary syndrome. One of the less favorable aspects of this medication is its price. The generic form of this medication has been available in Europe, Asia and since 2012 in United States of America. Another negative aspect of this medication is its tendency to cause low platelets (TTP) and consequent bleeding. Fortunately, this adverse effect is minimal and not a real concern if it is monitored, diagnosed early and treated appropriately. The report about the interaction between Plavix® and so-called proton pump inhibitors that are one of the most used drugs in managing heart burn (such as omeprazole and esomeprazole) has been concerning. In a study, patients who were on combination treatment of Plavix® and PPIs had a 25% increased risk of dying from heart related issues (Ho PM, JAMA. 2009 Mar 4; 301(9):937-44). Protonix (pantoprazole, Wyeth Pharmaceuticals) – has not shown any evidence of reducing the effectiveness of antiplatelet drugs including Plavix®.
The recent box warning concerning so- called poor metabolizers by FDA is also another thumbs down for this medication. There are subgroups of patients who are taking Plavix® without really benefiting from it. A genetic testing for CYP2C19 function has been suggested to identify this group of patients. The cost of this test has been estimated at around $500. The American College of Cardiology and the American Heart Association do not recommend routine genetic testing at this time. It has been suggested that patients that might be good candidates for genetic testing are those who had stent thrombosis while taking Clopidogrel.
This medication has been favored by many physicians for its ease of use, great benefits and limited scope of adverse effects.However, based on latest studies we have to be concerned for the subgroup of patients who may not receive the full benefit of the medication as may have been anticipated.
Disclaimer:
This Medication Guide summarizes the most important information (based on author’s personal opinion) about the above medication and is not a complete medication guide. If you would like more information, talk with your doctor and your pharmacist. The ultimate judgment regarding your care must be made by you and your physician together, in light of circumstances specific to you as a patient.
Plavix® is a registered trademark of Sanofi-Aventis.
Coumadin® is a registered trademark of Bristol-Myers Squibb Pharma Company.
Prilosec® is a registered trademark of AstraZeneca.
Jantoven® is a registered trademark of USL Pharma.
What is clopidogrel?
Clopidogrel oral tablet is a prescription drug that’s available as the brand-name drug Plavix. It’s also available as a generic drug. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand-name version.
Why it's used
Clopidogrel is used to prevent blood clots if you have chest pain, poor circulation in your legs (peripheral arterial disease), a heart attack, or stroke.
This drug may be used as part of a combination therapy. That means you may need to take it with other drugs. Your doctor will decide if you should use this drug with other drugs, such as aspirin.
How it works
Clopidogrel belongs to a class of drugs called platelet inhibitors or thienopyridine class inhibitors of P2Y12 ADP platelet receptors. A class of drugs refers to medications that work similarly. They have a similar chemical structure and are often used to treat similar conditions.
Platelets are blood cells that help your blood clot normally. Clopidogrel helps prevent platelets from sticking together. This stops them from forming blood clots.
Clopidogrel oral tablet is available as both a generic and brand-name drug. Brand name: Plavix
The most common side effect that occurs with clopidogrel is bleeding. This can be life-threatening. You should tell your doctors or dentists that you’re taking clopidogrel before having any procedures done. You may need to stop taking this drug for a short time before a procedure to prevent bleeding. Your doctor will let you know.
Clopidogrel is used to prevent heart attack and stroke. It is prescribed for people who have had a recent heart attack or stroke or peripheral arterial disease (poor circulation in your legs).
Serious bleeding warning: This drug can cause serious and sometimes fatal bleeding. Clopidogrel may make you bruise and bleed more easily, have nosebleeds, and it will take longer than usual for bleeding to stop. You should tell your doctor about any serious bleeding, such as:
unexplained, prolonged, or excessive bleeding
blood in your urine or stool
Warning for surgery or procedure: You should tell your doctors or dentists that you’re taking clopidogrel before having any procedures done. You may need to stop taking this drug for a short time before a procedure to prevent bleeding. Your doctor will let you know when to stop taking this medication and when it’s OK to take it again.
Plavix benefit found in heart failure patients
LONDON (Reuters) - Patients with heart failure who have had a heart attack but not had artery-clearing angioplasty treatment are less likely to die early if they take Sanofi-Aventis and Bristol-Myers Squibb’s drug Plavix, study data showed on Monday.
The study by Danish scientists published in the Journal of the American College of Cardiology was the first to look at the effect of the anti-clotting drug Plavix, known generically as clopidogrel, on death rates in specific high-risk patients with heart failure and heart attack.