Clopidogrel: Mechanism of Action, Side Effects & Drug Interactions

Instructor: Amy Couture

Amy has a master's degree in nursing and has taught nursing students at the college level.

Clopidogrel is used to prevent heart attacks and strokes in people with heart disease. This lesson discusses the mechanism of action, side effects, and drug interactions associated with clopidogrel.

What is clopidogrel?

Bob had a heart attack recently and was seen by his primary care physician for a follow-up appointment. At the appointment, the doctor started Bob on a medication called clopidogrel. Bob has never heard of this medication and asked the doctor for more information. The doctor stated that clopidogrel is an antiplatelet medication and sometimes called a ''blood thinner''. He said it is used to prevent strokes, heart attacks, and other heart problems. The more common name for clopidogrel is Plavix.

Mechanism of action

Bob wanted more information about this medication and asked the doctor how it works. The doctor explained that clopidogrel works by preventing platelets, which is a type of blood cell, from forming clots. A blood clot which forms inside a blood vessel, can cut off blood supply to the heart or brain which would cause a heart attack or stroke. The medication may cause an individual to bleed or bruise easily. The doctor explained that it may take Bob longer than normal to stop bleeding if he received a cut while he is on this medication. He also will need to stop this medication a week before any kind of surgery as it may prolong bleeding.

Clopidogrel helps prevent heart attacks and strokes.
Human heart

Side effects

Bob is nervous about the side effects associated with this medication and asks his doctor what he should look out for. The doctor states that if the following symptoms are severe or don't go away, Bob should let him know:

  • headache
  • dizziness
  • nausea
  • vomiting
  • excessive tiredness
  • nosebleed

The doctor also warned Bob that some of the side effects can be serious and he should be called if he is experiencing any of the following:

  • hives
  • rash
  • itching
  • hoarseness
  • red blood in stools
  • unusual bleeding or bruising
  • slow or difficult speech
  • shortness of breath
  • confusion

Drug interactions

As with any drug, interactions with other medications can occur. When Bob goes to pick up his prescription at the pharmacy, he asks the pharmacist what medications should he not take when taking clopidogrel. The pharmacist instructs Bob that he should not take any of the following medications since they also affect blood clotting.

  • aspirin
  • heparin
  • non steroidal anti-inflammatory drugs such as ibuprofen or naproxen
  • warfarin
  • antidepressants such as fluoxetine, paroxetine

The pharmacist also tells Bob that some medications make clopidogrel less effective and he should stay away from them.

  • carbamezapine
  • chloramphenicol
  • cimetidine
  • ciprofloxacin
  • fluconazole
  • fluoxetine
  • fluvoxamine
  • moclobemide
  • oxcarbazepine
  • ticlopidine
  • voriconazole

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