- A Visual Guide to Heart Disease
- Medical Illustrations of the Heart Image Collection
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- What is clopidogrel, and how does it work (mechanism of action)?
- What are the uses for clopidogrel?
- What are the side effects of clopidogrel?
- What is the dosage for clopidogrel?
- Which drugs or supplements interact with clopidogrel?
- Is clopidogrel safe to take if I'm pregnant or breastfeeding?
- What else should I know about this drug?
What is clopidogrel, and how does it work (mechanism of action)?
Clopidogrel bisulfate is an anti-platelet drug, that is, a drug that inhibits the ability of platelets to clump together as part of a blood clot. Clopidogrel prevents blood clots by irreversibly binding to the P2Y12 receptor on platelets, preventing adenosine diphosphate (ADP) from activating platelets. It belongs to a class of drugs called P2Y12 inhibitors. Other drugs in this class include ticagrelor (Brilinta) and prasugrel (Effient). Clopidogrel is similar to ticlopidine (Ticlid) in chemical structure and in the way it works. Unlike ticlopidine, clopidogrel bisulfate does not cause serious reductions of white cells in the blood and, therefore, routine blood testing to determine if the white blood cell count is low is not necessary during treatment. The risk of heart attacks and strokes (which usually are caused by blood clots) is increased in patients with a recent history of stroke or heart attack, and patients with peripheral vascular disease. (Peripheral vascular disease is the same as atherosclerotic arterial disease or "hardening" of the arteries in which the arteries become narrowed. It frequently occurs in the legs and often causes claudication or pain in the legs upon walking.) Clopidogrel bisulfate is used to reduce the risk of heart attacks and strokes in these patients. Clopidogrel bisulfate was approved by the FDA in 1997.
What are the uses for clopidogrel?
Clopidogrel is used for preventing strokes, heart attacks, and death in individuals who have had a previous stroke, unstable angina, heart attack or have peripheral arterial disease (PAD). The combination of clopidogrel and aspirin is better than aspirin or clopidogrel alone in preventing another heart attack but the risk of bleeding is higher.
What are the side effects of clopidogrel?
The tolerability of clopidogrel is similar to that of aspirin. The more common side effects of clopidogrel are:
- Abdominal pain
- chest pain,
- muscle aches,
- severe bleeding,
- allergic reactions,
- pancreatitis, and
- liver failure.
Ticlopidine (Ticlid) is an antiplatelet medication quite similar to clopidogrel. It has been associated with a severe reduction in white blood cell count in between 0.8% and 1% of persons. The risk of this dangerous side effect with clopidogrel is about 0.04%, much less than with ticlopidine but twice that of aspirin.
Clopidogrel rarely causes a condition called thrombotic thrombocytopenic purpura (TTP) in one out of every 250,000 people. TTP is a serious condition in which blood clots form throughout the body. Blood platelets, which participate in clotting, are consumed, and the result can be bleeding because enough platelets are no longer left to allow blood to clot normally. For comparison, the related drug, ticlodipine (Ticlid), causes TTP 17-50 times more frequently than clopidogrel.
What is the dosage for clopidogrel?
Clopidogrel bisulfate usually is taken once daily. It can be taken with or without food. Clopidogrel is activated by enzymes in the liver to its active form. Individuals who have reduced activity of liver enzymes that activate clopidogrel due to liver disease may not adequately respond to clopidogrel. Alternative treatments should be used for these patients. The recommended dose for treating unstable angina or heart attack is 300 mg initially followed by 75 mg daily in combination with 75-325 mg of aspirin. Peripheral arterial disease or recent stroke is treated with 75 mg daily.
Which drugs or supplements interact with clopidogrel?
The combination of clopidogrel with nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Motrin, Advil, Nuprin), naproxen (Naprosyn, Aleve), diclofenac (Voltaren), etodolac (Lodine), nabumetone (Relafen), fenoprofen (Nalfon), flurbiprofen (Ansaid), indomethacin (Indocin), ketoprofen (Orudis; Oruvail), oxaprozin (Daypro), piroxicam (Feldene), sulindac (Clinoril), tolmetin (Tolectin), and mefenamic acid (Ponstel) may increase the risk of stomach and intestinal bleeding.
Combining clopidogrel with warfarin (Coumadin) or other drugs that cause bleeding increases the risk of bleeding.
Clopidogrel is converted to its active form by enzymes in the liver. Drugs that reduce the activity of these enzymes, for example, omeprazole (Prilosec, Zegerid) or esomeprazole (Nexium) may reduce the activity of clopidogrel and should not be used with clopidogrel. Other drugs that also may react with clopidogrel in a similar fashion include fluoxetine (Prozac, Sarafem), cimetidine (Tagamet), fluconazole (Diflucan), ketoconazole (Nizoral, Extina, Xolegel, Kuric), voriconazole (Vfend), ethaverine (Ethatab, Ethavex), felbamate (Felbatol), and fluvoxamine (Luvox).
Quick GuideHeart Disease: Symptoms, Signs, and Causes
Is clopidogrel safe to take if I'm pregnant or breastfeeding?
There are no adequate studies of clopidogrel in pregnant women.
Studies in rats have shown that clopidogrel appears in breast milk; however, it is not known whether it also appears in human breast milk. Because of a potential for side effects in the nursing infant, the physician must weigh the potential benefits and possible risks before prescribing clopidogrel to nursing mothers.
What else should I know about this drug?
- Clopidogrel is avaialable as tablets: 75 and 300 mg. Tablets should be stored at room temperature, 15 C - 30 C (59 F - 86 F).
- Clopidogrel is available as a generic drug. You need a prescription from your doctor to obtain this medicine.
- Plavix is the brand name available for clopidogrel in the US.
Multimedia: Slideshows, Images & Quizzes
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Treatment & Diagnosis
- Stroke FAQs
- Deep Vein Thrombosis and Pulmonary Embolism FAQs
- Heart Attack Risk and Medicated Stents
- Medication Disposal
- Dangers of Mixing Medications
- How To Reduce Your Medication Costs
- Pharmacy Visit, How To Get The Most Out of Your Visit
- Indications for Drugs: Approved vs. Non-approved
- Drugs: Buying Prescription Drugs Online Safely
- Drugs: The Most Common Medication Errors
- Head Injury Symptoms, Types, and Severity
- Generic Drugs, Are They as Good as Brand-Names?
Medications & Supplements
- Aspirin vs. Plavix (clopidogrel)
- Drugs: Questions to Ask Your Doctor or Pharmacist about Your Drugs
- Drug Interactions
- Coumadin vs. Plavix (Differences and Similarities)
- Ibuprofen and Plavix (Side Effects and Interactions)
- Aspirin Therapy (Guidelines for Heart Attack and Stroke Prevention)
- cangrelor (Kengreal)
- ticlopidine, Ticlid (discontinued brand in the US)
Prevention & Wellness
- Study Tracks Bleeding Risk From Common Blood Thinners
- Research Points to 'Smoking Gun' for PPI Risks
- Many With Irregular Heartbeat Missing Out on Stroke-Preventing Treatments
- Side Effects Cause Some to Stop Taking Blood Thinner Brilinta
- Anti-Clotting Drug Approved For Angioplasty
- Stents Meant to Prevent Stroke May Actually Boost Risk
- Certain Painkillers Ill-Advised After Heart Attack: Study
- Aspirin 'Resistance' May Make for Worse Strokes: Study
- Long-Term Use of Aspirin Plus Blood Thinner Is Safe: Study
- Many Delay Blood Thinners After Stent Placement, Risking Death
- Statins Not Linked to Memory Loss, Dementia, Review Suggests
- Drug Combo May Reduce Risk of Second Stroke: Study
- Shopping Around Brings Steep Prescription Drug Savings, Report Finds
- New Drugs Might Give Heart Patients an Edge
- Giving Plavix Before Angioplasty May Cut Heart Attack Risk: Study
- Study Supports Use of 'Brain Stents' for Certain Stroke Patients
- More New Drugs a Bad Fit With Grapefruit, Study Finds
- Standard Dose of Blood Thinner May Not Be Best for All Patients
- Many Older Heart Attack Survivors Don't Stick With Meds
- Year of Taking Risky Blood Thinners May Be Unnecessary After Stent Surgery
- Adding Plavix to Aspirin Doesn't Help Guard Against Second Stroke: Study
- Daily Aspirin May Help Fight Prostate Cancer, But Not Breast Cancer
- New Blood Thinner Effient No Better Than Plavix at Preventing Heart Trouble: Study
- Guidelines Issued for New Blood Thinner Brilinta
- FDA Approves Generic Versions of Plavix
- Plavix's New Generic Status Could Be Boon for Patients
- Are Biodegradable Heart Stents Safe?
- Low-Dose Daily Aspirin Enough to Help Heart Attack Patients: Study
- Aspirin as Good as Plavix for Poor Leg Circulation: Study
- Doubt Cast on Use of Genetic Test Before Plavix
- FDA Rejects New Blood Thinner -- for Now
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Daily Health News
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