Most Common Effects

• In clinical studies with Plavix, as detailed by eMedTV, the most common side effects were headache, flu-like symptoms and dizziness, occurring in 6 percent to 7 percent of participants in some studies.
  
  

Other Side Effects

• Other side effects associated with Plavix include back or joint pain, bruising, diarrhea or constipation, indigestion, nosebleeds, rash and itchy skin.
  
  

Increased Bleeding

• Plavix can increase bleeding, which may cause problems when injuries occur. In some clinical trials, up to 3.7 percent of participants experienced major bleeding side effects.
  
  

Internal Bleeding

• Internal bleeding, such as gastrointestinal hemorrhage or bleeding ulcers, also may occur. Symptoms call for immediate medical attention. They include tarry or bloody stools, blood in the urine, coughing or vomiting blood, and red or purple spots on the skin.
  
  

Allergic Reaction

• Rarely, some people have an allergic reaction to Plavix. Signs are severe rash, itching, swelling, severe dizziness and difficulty breathing.