16 Dec Study Highlights Unpredictable Anticoagulation With Warfarin
MedicalResearch.com Interview with:
Winnie Nelson PharmD, MS, MBA
Director, Health Economics & Outcomes Research
Medical Research: What is the background for this study? What are the main findings?
Dr. Nelson: Although warfarin has long served as the standard of care for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF), research has shown nearly one-third of international normalized ratio (INR) levels among stabilized patients on warfarin are out-of-range. Data recently published in the International Journal of Clinical Pharmacy underscores the potential complications of out-of-range INRs, with the aim of informing patient care.
The analysis of a U.S. Veterans Health Administration dataset showed out-of-range INRs were associated with a significantly increased risk of adverse clinical outcomes, including stroke and major bleeding. Of particular interest, the study also showed the magnitude of risk of thromboembolic events – such as ischemic stroke – was several folds higher in sub-therapeutic INR levels (i.e., INR <2) than risk of bleeding events when INR measures were >3. In another words, the research found more risks to patients when INRs were too low than when INRs were too high.
Medical Research: What should clinicians and patients take away from your report?
Dr. Nelson: These findings highlight substantial barriers to care with warfarin, as unpredictable INR patterns, common with warfarin, may lead to poorer clinical outcomes. An awareness of this risk may help inform clinicians as they select an appropriate anticoagulant for patients. Once-daily XARELTO® is an oral anticoagulant approved to reduce the risk of stroke and systemic embolism in patients with NVAF, without the need for routine blood monitoring to manage INR levels.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Nelson: These findings complement previously published data, showing challenges associated with warfarin use. Findings from a separate study published in Current Medical Research and Opinion showed one quarter of patients newly initiated on warfarin failed to reach stable INR levels. Additionally, a systematic review of published literature, featured in Thrombosis Journal, showed patients with INRs outside therapeutic range accounted for a majority of thromboembolic and hemorrhagic events, with 56 percent of stroke cases occurring in patients across various studies with out-of-range INRs.
Given these risks, future research should aim to ensure doctors and patients are equipped with the latest information to optimize patient care. As such, Janssen continues to investigate the value of XARELTO®, an important medicine that offers an alternative to the standard of care, without the need for routine blood monitoring and no known dietary restrictions.
Out-of-range INR values and outcomes among new warfarin patients with non-valvular atrial fibrillation
Nelson WW1, Wang L, Baser O, Damaraju CV, Schein JR.
Int J Clin Pharm. 2014 Nov 27. [Epub ahead of print]
About XARELTO® (rivaroxaban)
XARELTO® works by blocking the blood clotting Factor Xa. XARELTO® does not require routine blood monitoring. XARELTO® has a broad indication profile and is approved for six indications that include:
- To reduce the risk of strokes and blood clots in patients with atrial fibrillation not caused by a heart valve problem. For patients currently well managed on warfarin, there is limited information on how XARELTO® and warfarin compare in reducing the risk of stroke.
- To treat patients with deep vein thrombosis (DVT).
- To treat patients with pulmonary embolism (PE).
- To reduce the risk of recurrence of DVT or PE following an initial six-month treatment for acute venous thromboembolism.
- To reduce the risk of blood clots in the legs and lungs of patients who have just had knee replacement surgery.
- To reduce the risk of blood clots in the legs and lungs of patients who have just had hip replacement surgery.
Janssen and Bayer HealthCare together are developing rivaroxaban.
IMPORTANT SAFETY INFORMATION:
WHAT IS THE MOST IMPORTANT INFORMATION I SHOULD KNOW ABOUT XARELTO®?
- For people taking XARELTO® for atrial fibrillation:
People with atrial fibrillation (an irregular heart beat) are at an increased risk of forming a blood clot in the heart, which can travel to the brain, causing a stroke, or to other parts of the body. XARELTO® lowers your chance of having a stroke by helping to prevent clots from forming. If you stop taking XARELTO®, you may have increased risk of forming a clot in your blood.
Do not stop taking XARELTO® without talking to the doctor who prescribes it for you. Stopping XARELTO® increases your risk of having a stroke.
If you have to stop taking XARELTO®, your doctor may prescribe another blood thinner medicine to prevent a blood clot from forming.
- XARELTO® can cause bleeding, which can be serious, and rarely may lead to death. This is because XARELTO® is a blood thinner medicine that reduces blood clotting. While you take XARELTO® you are likely to bruise more easily and it may take longer for bleeding to stop.
You may have a higher risk of bleeding if you take XARELTO® and take other medicines that increase your risk of bleeding, including:
- Aspirin or aspirin-containing products
- Non-steroidal anti-inflammatory drugs (NSAIDs)
- Warfarin sodium (Coumadin®, Jantoven®)
- Any medicine that contains heparin
- Clopidogrel (Plavix®)
- Other medicines to prevent or treat blood clots
Tell your doctor if you take any of these medicines. Ask your doctor or pharmacist if you are not sure if your medicine is one listed above.
Call your doctor or get medical help right away if you develop any of these signs or symptoms of bleeding:
- Unexpected bleeding or bleeding that lasts a long time, such as:
- Nosebleeds that happen often
- Unusual bleeding from gums
- Menstrual bleeding that is heavier than normal, or vaginal bleeding
- Bleeding that is severe or that you cannot control
- Red, pink, or brown urine
- Bright red or black stools (looks like tar)
- Cough up blood or blood clots
- Vomit blood or your vomit looks like “coffee grounds”
- Headaches, feeling dizzy or weak
- Pain, swelling, or new drainage at wound sites
Spinal or epidural blood clots (hematoma): People who take a blood thinner medicine (anticoagulant) like XARELTO®, and have medicine injected into their spinal and epidural area, or have a spinal puncture, have a risk of forming a blood clot that can cause long-term or permanent loss of the ability to move (paralysis). Your risk of developing a spinal or epidural blood clot is higher if:
- A thin tube called an epidural catheter is placed in your back to give you certain medicine
- You take NSAIDs or a medicine to prevent blood from clotting
- You have a history of difficult or repeated epidural or spinal punctures
- You have a history of problems with your spine or have had surgery on your spine
If you take XARELTO® and receive spinal anesthesia or have a spinal puncture, your doctor should watch you closely for symptoms of spinal or epidural blood clots. Tell your doctor right away if you have back pain, tingling, numbness, muscle weakness (especially in your legs and feet), or loss of control of the bowels or bladder (incontinence).
XARELTO® is not for patients with artificial heart valves.
WHO SHOULD NOT TAKE XARELTO®?
Do not take XARELTO® if you:
- Currently have certain types of abnormal bleeding. Talk to your doctor before taking XARELTO® if you currently have unusual bleeding.
- Are allergic to rivaroxaban or any of the ingredients of XARELTO®.
WHAT SHOULD I TELL MY DOCTOR BEFORE OR WHILE TAKING XARELTO®?
Before taking XARELTO®, tell your doctor if you:
- Have ever had bleeding problems
- Have liver or kidney problems
- Have any other medical condition
- Are pregnant or plan to become pregnant. It is not known if XARELTO® will harm your unborn baby. Tell your doctor right away if you become pregnant while taking XARELTO®. If you take XARELTO® during pregnancy, tell your doctor right away if you have bleeding or symptoms of blood loss.
- Are breastfeeding or plan to breastfeed. It is not known if XARELTO® passes into your breast milk. You and your doctor should decide if you will take XARELTO® or breastfeed.
Tell all of your doctors and dentists that you are taking XARELTO®. They should talk to the doctor who prescribed XARELTO® for you before you have any surgery, medical or dental procedure.
Tell your doctor about all the medicines you take, including prescription and nonprescription medicines, vitamins, and herbal supplements. Some of your other medicines may affect the way XARELTO® works. Certain medicines may increase your risk of bleeding. See “What is the most important information I should know about XARELTO®?”
Especially tell your doctor if you take:
- Ketoconazole (Nizoral®)
- Itraconazole (Onmel™, Sporanox®)
- Ritonavir (Norvir®)
- Lopinavir/ritonavir (Kaletra®)
- Indinavir (Crixivan®)
- Carbamazepine (Carbatrol®, Equetro®, Tegretol®, Tegretol®-XR, Teril™, Epitol®)
- Phenytoin (Dilantin-125®, Dilantin®)
- Phenobarbital (Solfoton™)
- Rifampin (Rifater®, Rifamate®, Rimactane®, Rifadin®)
- St. John’s wort (Hypericum perforatum)
Ask your doctor if you are not sure if your medicine is one listed above. Know the medicines you take. Keep a list of them to show your doctor and pharmacist when you get a new medicine.
HOW SHOULD I TAKE XARELTO®?
Take XARELTO® exactly as prescribed by your doctor.
Do not change your dose or stop taking XARELTO® unless your doctor tells you to.
- Your doctor will tell you how much XARELTO® to take and when to take it.
- Your doctor may change your dose if needed.
If you take XARELTO® for:
- Atrial Fibrillation: Take XARELTO® 1 time a day with your evening meal.
If you miss a dose of XARELTO®, take it as soon as you remember on the same day. Take your next dose at your regularly scheduled time.
- Blood clots in the veins of your legs or lungs:
- Take XARELTO® once or twice a day as prescribed by your doctor.
- Take XARELTO® with food at the same time each day.
- If you miss a dose of XARELTO®:
- and take XARELTO® 2 times a day: Take XARELTO® as soon as you remember on the same day. You may take 2 doses at the same time to make up for the missed dose. Take your next dose at your regularly scheduled time.
- and take XARELTO® 1 time a day: Take XARELTO® as soon as you remember on the same day. Take your next dose at your regularly scheduled time.
- Hip or knee replacement surgery: Take XARELTO® 1 time a day with or without food. If you miss a dose of XARELTO®, take it as soon as you remember on the same day. Take your next dose at your regularly scheduled time.
- If you have difficulty swallowing the tablet whole, talk to your doctor about other ways to take XARELTO®.
- Your doctor will decide how long you should take XARELTO®. Do not stop taking XARELTO® without talking to your doctor first.
- Your doctor may stop XARELTO® for a short time before any surgery, medical or dental procedure. Your doctor will tell you when to start taking XARELTO® again after your surgery or procedure.
- Do not run out of XARELTO®. Refill your prescription for XARELTO® before you run out. When leaving the hospital following a hip or knee replacement, be sure that you have XARELTO® available to avoid missing any doses.
- If you take too much XARELTO®, go to the nearest hospital emergency room or call your doctor right away.
WHAT ARE THE POSSIBLE SIDE EFFECTS OF XARELTO®?
Please see “What is the most important information I should know about XARELTO®?” above.
Tell your doctor if you have any side effect that bothers you or that does not go away.
Call your doctor for medical advice about side effects. You are also encouraged to report side effects to the FDA: visit http://www.fda.gov/medwatch or call 1-800-FDA-1088. You may also report side effects to Janssen Pharmaceuticals, Inc., at 1-800-JANSSEN (1-800-526-7736).
Please click here for full Prescribing Information, including Boxed Warnings, and Medication Guide.