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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.
Quick GuideHeart Disease: Symptoms, Signs, and Causes
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).
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
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
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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...
DVT in Pictures: Symptoms of Deep Vein Thrombosis, Beyond Leg Pain and More
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Stroke Causes, Symptoms, and Recovery
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Related Disease Conditions
14 Signs and Symptoms of Stroke (FAST)
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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...
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,...
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...
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...
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...
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...
Blood clots can occur in the venous and arterial vascular system. Blood clots can form in the heart, legs, arteries, veins,...
Intermittent claudication, or pain and cramping in the lower leg is caused by inadequate blood flow to the leg muscles. This lack...
Heart attack happens when a blood clot completely obstructs a coronary artery supplying blood to the heart muscle. A heart attack...
Transient Ischemic Attack (TIA, Mini-Stroke)
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Heart Attack vs. Stroke Symptoms, Differences, and Similarities
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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...
Stroke vs. Mini-Stroke (TIA)
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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...
Heart Attack Treatment
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Stroke vs Aneurysm (Differences and Similarities)
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Atrial Fibrillation (AFib) Treatment Drugs
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Heart Attack Prevention
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Treatment & Diagnosis
- Stroke FAQs
- Deep Vein Thrombosis and Pulmonary Embolism FAQs
- 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
- Heart Attack Risk and Medicated Stents
- Medication Disposal
- Dangers of Mixing Medications
- Head Injury Symptoms, Types, and Severity
- Generic Drugs, Are They as Good as Brand-Names?
Medications & Supplements
- Drugs: What You Should Know About Your Drugs
- Drug Interactions
- Aspirin vs. Plavix (clopidogrel)
- Aspirin Therapy (Guidelines for Heart Attack and Stroke Prevention)
- Ibuprofen and Plavix (Side Effects and Interactions)
- Coumadin vs. Plavix (Differences and Similarities)
- ticlopidine, Ticlid (discontinued brand in the US)
- cangrelor (Kengreal)
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
Quick GuideHeart Disease: Symptoms, Signs, and Causes
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Top clopidogrel Related Articles
11 Signs and Symptoms of Stroke
Stroke is a serious medical condition. If you think you or someone you know is having a stroke call 911 immediately.
There are two main types of strokes, hemorrhagic and ischemic (the most common type).
A hemorrhagic stroke occurs due to a blood vessel rupture in the brain. An ischemic stroke occurs when a blood clot becomes lodged in a blood vessel in the brain, which causes a loss of blood supply to the brain, possibly causing brain tissue death.
FAST is an acronym that helps people identify stroke signs and symptoms so they can act fast and call 911. Face drooping, Arm weakness, and Speech difficulty are indicators that a person may be having a stroke and it is Time to seek emergency medical treatment. Additional signs and symptoms of stroke may include weakness, difficulty walking, blurred vision, dizziness, headache, confusion, difficulty speaking, and loss of sensation. .
Stroke is a major cause of death and disability in the US. Early identification and treatment of stroke helps reduce the risk of morbidity and mortality.
Blood clots can occur in the venous and arterial vascular system. Blood clots can form in the heart, legs, arteries, veins, bladder, urinary tract and uterus. Risk factors for causes of blood clots include
- high blood pressure and cholesterol,
- smoking, and
- family history.
Symptoms of a blood clot depend on the location of the clot. Some blood clots are a medical emergency. Blood clots are treated depending upon the cause of the clot. Blood clots can be prevented by lowering the risk factors for developing blood clots.
ClaudicationIntermittent claudication, or pain and cramping in the lower leg is caused by inadequate blood flow to the leg muscles. This lack of blood flow causes a decrease in oxygen delivered to the muscles of the legs. Claudication is generally felt when walking and decreases with rest. In severe cases, claudication may be felt at rest. Narrowing of arteries cause claudication. Treatment includes exercise, medication, and in some cases surgery.
Deep Vein Thrombosis
Deep vein thrombosis (DVT) is a blood clot in the deep veins, and can be caused by broken bones, trauma to a limb, immobility, medications, smoking, cancer, genetic predisposition, and cancer. Symptoms of a deep vein thrombosis in a leg are
- warmth, and
Treatment for DVT include medications and surgery.
Take the DVT QuizTake the Deep Vein Thrombosis and Pulmonary Embolism Quiz to learn causes, symptoms, and treatments for these two dangerous conditions.
DVT SlideshowDeep vein thrombosis (DVT) is a dangerous and sometimes fatal blood clot that occurs deep within the lower leg or thigh. Understand the symptoms, treatment and prevention of deep vein thrombosis (DVT).
Heart AttackHeart attack happens when a blood clot completely obstructs a coronary artery supplying blood to the heart muscle. A heart attack can cause chest pain, heart failure, and electrical instability of the heart.
Heart SymptomsHeart attacks symptoms vary greatly for men and women, from anxiety and fatigue to nausea and sweating. Learn the warning signs of a heart attack and know the symptoms that may require an immediate trip to the hospital.
Illustrations of the HeartThe muscle that pumps blood received from veins into arteries throughout the body. See a picture of the Heart and learn more about the health topic.
Heart: How the Heart WorksThe heart is a very important organ in the body. It is responsible for continuously pumping oxygen and nutrient-rich blood throughout your body to sustain life. It is a fist-sized muscle that beats (expands and contracts) 100,000 times per day, pumping a total of five or six quarts of blood each minute, or about 2,000 gallons per day.
Internal BleedingInternal bleeding occurs when an artery or vein is damaged and blood to escapes the circulatory system and collects inside the body. Internal bleeding can be caused by a variety of situations such as blunt trauma, deceleration trauma, medications, fractures, and spontaneous bleeding. Treatment of internal bleeding depends on the cause of the bleeding.
Peripheral Vascular Disease
Peripheral vascular disease (PVD) refers to diseases of the blood vessels (arteries and veins) located outside the heart and brain. While there are many causes of peripheral vascular disease, doctors commonly use the term peripheral vascular disease to refer to peripheral artery disease (peripheral arterial disease, PAD), a condition that develops when the arteries that supply blood to the internal organs, arms, and legs become completely or partially blocked as a result of atherosclerosis. Peripheral artery disease symptoms include intermittent leg pain while walking, leg pain at rest, numbness in the legs or feet, and poor wound healing in the legs or feet.
Treatment for peripheral artery disease include lifestyle measures, medication, angioplasty, and surgery.
Pulmonary EmbolismA pulmonary embolism (PE) occurs when a piece of a blood clot from deep vein thrombosis (DVT) breaks off and travels to an artery in the lung where it blocks the artery and damages the lung. The most common symptoms of a pulmonary embolism are shortness of breath, chest pain, and a rapid heart rate. Causes of pulmonary embolism include prolonged immobilization, certain medications, smoking, cancer, pregnancy, and surgery. Promt medical attention should be sought if you think you or someome you know has a pulmonary embolus.
Stroke SlideshowWhat is a stroke? Learn about stroke symptoms like sudden numbness or weakness, confusion, vision problems, or problems with coordination. Discover causes and recovery of a stroke.
Take the Stroke QuizTake the Stroke Quiz to learn about stroke risks, causes, treatment, and most importantly, prevention.
Stroke Symptoms and Treatment
A stroke is an interruption of the blood supply to part of the brain caused by either a blood clot (ischemic) or bleeding (hemorrhagic). Symptoms of a stroke may include
- double vision or vision loss,
- vertigo, and
- difficulty speaking or understanding speech.
A physical exam, imaging tests, neurological exam, and blood tests may be used to diagnose a stroke. Treatment may include administration of clot-busting drugs, supportive care, and in some instances, neurosurgery. The risk of stroke can be reduced by controlling high blood pressure, high cholesterol, diabetes, and stopping smoking.