Pradaxa Risks: What Patients Need to Know Before Switching from Coumadin
What is Pradaxa?
Pradaxa is one of a new class of blood thinners, or anticoagulants, known as direct thrombin inhibitors. These oral drugs are used to prevent blood clotting and stroke in patients with nonvalvular atrial fibrillation, a dangerous form of irregular heartbeat. Approved by the U.S. Food and Drug Administration in October 2010 and manufactured by Boehringer Ingelheim Pharmaceuticals, Inc. (Ridgefield, CT), Pradaxa is the first anticoagulant that has been released for this treatment in more than 50 years.
Prior to the approval of Pradaxa, Coumadin® (warfarin) was the only oral anticoagulant available in the U.S. for stroke reduction in patients with atrial fibrillation. Pradaxa was designed to replace warfarin, which requires routine blood monitoring and a restricted diet.
To who is Pradaxa prescribed?
Pradaxa is prescribed to patients who have atrial fibrillation (an irregular heartbeat). This condition is one of the most common types of abnormal heart rhythms, affecting more than two million Americans, usually the elderly. The number of atrial fibrillation patients is expected to increase to 5.6 million by 2050. Atrial fibrillation is caused by quick and uncoordinated contractions of the heart’s two upper chambers (atria). These patients are at risk of developing blood clots that may cause a stroke if the clots migrate to the brain. This condition increases the risk of stroke by five times. Atrial fibrillation is associated with up to 15% of stroke cases in the U.S., and strokes caused by this condition are twice as likely to be fatal as those unrelated to atrial fibrillation.
How does Pradaxa work?
Pradaxa inhibits thrombin, a blood enzyme that plays a part in clotting. Pradaxa is taken orally, with or without food, and is available in 75 and 150 mg capsules (usual dose is 150 mg taken twice daily; patients with renal impairment take 75 mg twice daily). Pradaxa is contraindicated in patients with active pathological bleeding and those who have a known serious hypersensitivity reaction (e.g., anaphylactic reaction or anaphylactic shock) to Pradaxa.
What are the most recently disclosed side effects of Pradaxa?
Following trials involving over 30,000 patients and seven separate studies, researchers at the Cleveland Clinic concluded that Pradaxa is significantly associated with a 33% higher risk of acute coronary syndrome and heart attack when compared to patients not taking the drug. Results were published online in the Archives of Internal Medicine in January 2012.
Pradaxa Side Effects Can Lead to More Serious Issues
Pradaxa use carries serious side effects including the risk of bleeding. Clinical trials demonstrated that up to 16.6% of users experienced some degree of internal bleeding and that 17.4% of patients taking Pradaxa prior to surgery suffered major internal bleeding. Serious bleeding can occur in up to 3.3% of patients, life-threatening bleeding in up to 1.5%, and bleeding in the brain in up to 0.3%.
Signs and Symptoms of Bleeding are:
- Unusual bruising (develop without known cause or grow in size)
- Blood in the urine (seen as pink or brown)
- Blood in the stool (usually seen as red or black)
- Bleeding gums
- Bleeding cuts that take a long time to stop
- Menstrual bleeding that is heavier than normal
- Coughing up blood
- Vomiting blood or material resembling coffee grounds
- Low blood pressure
Other serious symptoms include weakness or swelling of the extremities, swollen or painful joints, dizziness, headaches, and lethargy. The most commonly reported side effect is gastrointestinal upset. Gastrointestinal upset can include:
- Abdominal (stomach) pain
- Gastroesophageal Reflux Disease (GERD)
- Ulcers of the digestive tract
As with any drug, patients can experience an allergic reaction to Pradaxa. Signs of an allergic reaction are:
- Unexplained rash
- Swelling of the mouth or throat
- Difficulty breathing