Clopidogrel is used alone or together with aspirin to lessen the chance of a heart attack or stroke. It is given to patients who have already had a heart attack, severe chest pain, or a stroke, or to patients with other circulation problems that could cause a stroke or heart attack.

A heart attack or stroke may occur when a blood vessel is blocked by a blood clot. Clopidogrel is a platelet inhibitor. It reduces the chance that a harmful blood clot will form by preventing platelets from clumping together in the blood. Clopidogrel may also increase the chance of serious bleeding in some people.

This medicine is available only with your doctor's prescription.

Take this medicine exactly as directed by your doctor. Clopidogrel will not work properly if you take less of it than directed. Taking more clopidogrel than directed may increase the chance of serious side effects without increasing the helpful effects.

This medicine comes with a Medication Guide. It is very important that you read and understand this information. Be sure to ask your doctor about anything you do not understand.

You may take this medicine with or without food.

If you are also taking omeprazole (Prilosec®), do not use it at the same time that you take this medicine. Talk with your doctor about using a different antacid.

If you are using this medicine for a condition called acute coronary syndrome, your doctor may tell you to take aspirin while you are using clopidogrel. In this case, do not change the dose or stop taking the aspirin without talking to your doctor first.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Chest pain

collection of blood under the skin

deep, dark purple bruise

itching, pain, redness, or swelling

pain in general

red or purple spots on the skin, varying in size from pinpoint to large bruises

Less common

Nosebleed

painful or difficult urination

shortness of breath

vomiting of blood or material that looks like coffee grounds

Rare

Black, tarry stools

blistering, flaking, or peeling of the skin

blood in the urine or stools

confusion

fever, chills, or sore throat

headache (sudden, severe)

nausea or vomiting

stomach pain (severe)

ulcers, sores, or white spots in the mouth

unusual bleeding or bruising

weakness (sudden)

Incidence not known

Abdominal or stomach cramps or swelling

back pain or backaches

blurred vision

change in mental status

cough or hoarseness

dark urine

difficulty with breathing or swallowing

difficulty with speaking

dizziness

dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position

fast heartbeat

feeling of discomfort

general feeling of tiredness or weakness

hives

inflammation of the joints

itching

light-colored stools

lower back or side pain

muscle aches

pale color of the skin

puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

rash

reddening of the skin, especially around the ears

seizures

sweating

swelling of the eyes, face, or inside of the nose

swollen lymph glands

swollen or painful glands

tightness in the chest

unusual tiredness or weakness

upper right abdominal or stomach pain

watery or bloody diarrhea

wheezing

yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known

Bad, unusual, or unpleasant (after) taste

bloating

change in taste

constipation

diarrhea

difficulty with moving

headache

hives or welts

indigestion

loss of appetite

muscle pain or stiffness

noisy breathing

pain in the joints

pains in the stomach, side, or abdomen, possibly radiating to the back

redness, soreness, or itching skin

seeing, hearing, or feeling things that are not there

skin blisters

sores, welting, or blisters

swelling or inflammation of the mouth

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

It is very important that your doctor check your progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood tests may be needed to check for unwanted effects.

Your doctor may do a genetic test before prescribing this medicine to determine if you have a deficiency in a liver enzyme called CYP2C19. This medicine may not work as well if you have this condition.

Tell all medical doctors, dentists, nurses, and pharmacists you go to that you are taking this medicine. Clopidogrel may increase the risk of serious bleeding during a surgery, other medical procedures (e.g., coronary stent procedure), or some kinds of dental work. You may need to stop using this medicine at least 5 days before a surgery, medical procedure, or dental work. Do not stop taking your medicine without your doctor's permission.

While you are using this medicine, if you have any kind of bleeding, it may take longer than usual to stop, especially if you hurt yourself. Stay away from rough sports or other situations where you could be bruised, cut, or injured. Be careful when using sharp objects, including razors and fingernail clippers.

This medicine may increase your chance of bleeding or bruising. Check with your doctor right away if you notice any unusual bleeding or bruising; black, tarry stools; blood in the urine or stools; or pinpoint red spots on your skin. Avoid picking your nose. If you need to blow your nose, blow it gently.

Do not change your dose or stop taking this medicine without checking first with your doctor.

Check with your doctor right away if you have the following symptoms: change in mental status, dark or bloody urine, difficulty with speaking, fever, pale color of the skin, pinpoint red spots on the skin, seizures, weakness, yellow eyes or skin. These maybe symptoms of a rare and serious condition called thrombotic thrombocytopenic purpura (TTP).

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.