Merck & Co., Ltd., the manufacturer of VIOXX, has agreed to a very large settlement amount in a class action suit (see The VIOXX Saga: Part 2). The many people who filed lawsuits against Merck had a variety of health problems associated with having taken VIOXX for several months or longer.

Serious VIOXX Side Effects

  • Heart attacks – not always fatal
  • Strokes – also not always fatal. Strokes and heart attacks can be caused by blocked blood vessels
  • Blood clots – which can block a blood vessel and cause strokes and heart problems
  • Stomach problems – intestinal bleeding can happen without warning and may require hospitalization. This is rare.
  • Allergic reactions – which can cause breathing troubles if the throat or mouth becomes swollen


  • Kidney problems – another rare side effect which could perhaps cause kidney failure
  • Liver problems – also very rare

Minor VIOXX Side Effects

This is a partial list of non-life-threatening side effects:

  • Respiratory tract inflammation or infection
  • Headache and back ache
  • Fatigue
  • Stomach pain
  • Dizziness
  • Nausea
  • Urinary tract infection
  • Meningitis
  • Elevated blood pressure
  • Irregular heartbeat

How VIOXX works

VIOXX is one of a groups of drugs which are alternatives to steroids. The group is called NSAIDs (for Non-Steroidal Anti-Inflammatory drug). Steroids reduce inflammation (which helps reduce pain) for a short while, but when taken for too long they cause a list of unpleasant side effects. So NSAIDs are used whenever possible. Other NSAIDs are aspirin, naproxen and ibuprofen. Acetaminophen is not an NSAID.

VIOXX prevents the formation of compounds called prostaglandins, which are thought to cause pain and inflammation. It is a “Cox-2 inhibitor”, meaning that it blocks the action of a body enzyme nicknamed Cox-2.

Unlike the other NSAIDs, it does not block Cox-1, whose job is to maintain stomach tissue, protecting the stomach lining. This gives VIOXX the advantage of being able to reduce pain and inflammation without causing stomach bleeding or ulcers. (Most people know that aspirin can cause gastrointestinal bleeding – it blocks Cox-1.)

VIOXX Questions

Questions have been asked about VIOXX since soon after it was approved by the FDA. Studies suggested an unacceptable risk of heart problems, and although Merck denied there was any evidence of that, compared to other NSAIDs, the FDA sent that warning letter to Merck in 2001 (see The VIOXX Saga: Part 1 in this space).

Lawsuits followed, as outlined in previous blogs here. Merck issued a statement after the November, 2007 class action suit agreement. It states the conditions those class action plaintiffs must meet to qualify for payment from Merck.

If you have taken VIOXX and suffered any of the side effects listed above, or others which you think are connected to VIOXX, contact your doctor immediately. Please also feel free to contact us to learn more about your legal options.