- A Visual Guide to Heart Disease
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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.
Healthy Heart Resources
Multimedia: Slideshows, Images & Quizzes
DVT (Deep Vein Thrombosis) and Pulmonary Embolism (PE) Quiz
Take the Deep Vein Thrombosis and Pulmonary Embolism Quiz to learn causes, symptoms, and treatments for these two dangerous...
Stroke Quiz: Test Your Medical IQ
Take the Stroke Quiz to learn about stroke risks, causes, treatment, and most importantly, prevention....
Picture of Peripheral Vascular Disease
Diabetes also affects the blood vessels and alters the flow of blood. See a picture of Peripheral Vascular Disease and learn more...
Picture of Blood Clot
Blood that has been converted from a liquid to a solid state. See a picture of Blood Clot and learn more about the health topic....
Picture of Heart
The muscle that pumps blood received from veins into arteries throughout the body. See a picture of the Heart and learn more...
Stroke Causes, Symptoms, and Recovery
What is a stroke? Learn about stroke symptoms like sudden numbness or weakness, confusion, vision problems, or problems with...
Am I Having a Heart Attack? Symptoms of Heart Disease
Heart attacks symptoms vary greatly for men and women, from anxiety and fatigue to nausea and sweating. Learn the warning signs...
DVT in Pictures: Symptoms of Deep Vein Thrombosis, Beyond Leg Pain and More
Deep vein thrombosis (DVT) is a dangerous and sometimes fatal blood clot that occurs deep within the lower leg or thigh....
Related Disease Conditions
A heart attack happens when a blood clot completely obstructs a coronary artery supplying blood to the heart muscle. A heart...
Stroke (Signs, Symptoms, Warning Signs)
A stroke is an interruption of the blood supply to part of the brain caused by either a blood clot (ischemic) or bleeding...
Peripheral Vascular Disease (PVD Symptoms, Signs, Causes, Treatments)
Peripheral vascular disease (PVD) refers to diseases of the blood vessels (arteries and veins) located outside the heart and...
Intermittent claudication, or pain and cramping in the lower leg is caused by inadequate blood flow to the leg muscles. This lack...
Heart Attack Prevention
Heart disease and heart attacks can be prevented by leading a healthy lifestyle with diet, exercise, and stress management....
Stroke is the third leading killer in the United States. Some of the warning signs of stroke include sudden confusion, trouble...
Deep Vein Thrombosis (DVT, Blood Clot in the Legs)
Deep vein thrombosis (DVT) is a blood clot in the deep veins, and can be caused by broken bones, trauma to a limb, immobility,...
How the Heart Works
The heart is a very important organ in the body. It is responsible for continuously pumping oxygen and nutrient-rich blood...
Carotid Artery Disease
The term carotid artery disease refers to the narrowing of the carotid arteries and can also be called carotid stenosis. Fatty...
Heart Attack Treatment
A heart attack involves damage or death of part of the heart muscle due to a blood clot. The aim of heart attack treatment is to...
Transient Ischemic Attack (TIA, Mini-Stroke)
When a portion of the brain loses blood supply, through a blood clot or embolus, a transient ischemic attack (TIA, mini-stroke)...
Pulmonary Embolism (Blood Clot in the Lung)
A pulmonary embolism (PE) occurs when a piece of a blood clot from deep vein thrombosis (DVT) breaks off and travels to an artery...
Blood clots can occur in the venous and arterial vascular system. Blood clots can form in the heart, legs, arteries, veins,...
Internal Bleeding (Symptoms, Signs, Causes, Treatment)
Internal bleeding occurs when an artery or vein is damaged and blood to escapes the circulatory system and collects inside the...
Heart Attacks in Women
Heart disease, particularly coronary artery disease is the leading cause of heart attacks. Women are more likely to die from a...
14 Signs and Symptoms of Stroke (FAST)
Stroke is a serious medical condition. If you think you or someone you know is having a stroke call 911 immediately....
Stroke vs Aneurysm (Differences and Similarities)
A stroke or "brain attack" is caused because blood flow to an area of the brain has been cut off by a blood clot or by a weakened...
Heart Attack vs. Stroke Symptoms, Differences, and Similarities
Heart attack usually is caused by a clot that stops blood flow supplying oxygen to an area of heart muscle, which results in...
Heart Attack vs. Heartburn (Differences between Symptoms and Signs)
Heartburn is a symptom of another disease or medical problem and can be described as a feeling of burning in the chest...
Stroke vs. Mini-Stroke (TIA)
A stroke or "brain attack" occurs when a blood clot or artery ruptures within the brain. The rupture or clot causes...
Migraine and Stroke (Symptoms, Types, Causes, Treatment)
Migraine headache is a type of headache in which the exact cause is not known; however, they may be inherited, and certain...
Atrial Fibrillation (AFib) Treatment Drugs
Atrial fibrillation (also called Afib or Afib) is heart rhythm disorder that causes irregular, and often, a rapid heartbeat. The...
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
- ticlopidine, Ticlid (discontinued brand in the US)
- Drugs: Questions to Ask Your Doctor or Pharmacist about Your Drugs
- Drug Interactions
- Aspirin Therapy (Guidelines for Heart Attack and Stroke Prevention)
- cangrelor (Kengreal)
- Coumadin vs. Plavix (Differences and Similarities)
- Ibuprofen and Plavix (Side Effects and Interactions)
- Aspirin vs. Plavix (clopidogrel)
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
- $1,000 Personal Genome Coming: Are We Ready?
- New Plavix Warning: Lack of Effect in Many People
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