March Meeting, Riverview

While we ate our lunch of wraps, green salad and fruit salad, Sheila Turkel introduced Viktoriya Fridman, a Clinical Specialist in the Pharmacy Department, to help with some uncertainties that patients have about blood thinners - medications that slow the formation of blood clots. These include warfarin, also known as Coumadin, and several antiplatelet medications: aspirin, Plavix and a newer medication, Effient. A 2006 survey of 4 million Americans taking blood thinners to prevent strokes, heart attacks, or blood clot formation found that many of them needed help managing these mediations.

Coumadin is the brand name for the generic warfarin. It’s an anticoagulant - it keeps the blood from coagulating (gelling or solidifying). Patients take it if they have a high risk of forming blood clots that could cause stroke or heart attack. It works by decreasing the activity of Vitamin K, which is essential for the clotting process.

It’s important to take warfarin once a day, at the same time every day. It’s best to take it in the evening. Viktoriya suggested a seven-day pill box to avoid skipping our doubling doses: if the pill is there, you didn’t take it yet; if it isn’t, you did.

Usually there’s no difference between branded and generic medications, but in this case the amount in your system could be different, so stick with whichever one you’re taking.

Your doctor determines the dosage by testing your INR (International Normalized Ratio), which measures how fast your blood clots. The dosage will be adjusted to keep your INR between 2 and 3 (normal INR is about 1). If it’s lower than 2, your blood is too likely to clot, and the dosage will be increased. If it’s above 3, you’re at risk for bleeding, and the dosage will be reduced or you may be told to skip a dose. It’s a narrow range, so it’s important to take warfarin consistently, have your INR checked regularly and follow the doctor’s instructions.

Also keep your Vitamin K intake consistent, because warfarin acts on Vitamin K. For instance, if you have a salad twice a week, you should do that every week. Green leafy vegetables contain large amounts of Vitamin K, other foods have less - the handout listed specific foods.

Avoid alcohol. Tests show that binge drinking raises INR (risk of bleeding), while chronic drinking lowers INR (risk of clotting). One glass of wine at a special event might be OK.

Some foods affect INR in other ways: cranberry juice and grapefruit juice raise INR; green tea lowers it.

Many common medications raise INR. Some antibiotics kill the gut bacteria that produce Vitamin K. Amiodarone, used to treat irregular heartbeat, can raise INR enough to require a lower dose of warfarin. Some heartburn medications raise INR, as do NSAIDS (including over-the-counter pain relievers) and aspirin. Tylenol is OK if used occasionally. A few medications lower INR.

Many herbal medications and supplements also raise INR; a few lower it. Vitamin E raises INR - don’t take more than 400 IU a day. Avoid herbal medications - their potency isn’t standardized.

The message to remember is to keep a delicate balance. First, be consistent, don’t start or stop anything without consulting your doctor (and/or your pharmacist - who may know more about medications than your doctor). Second, if you must start or stop something that affects your INR, you will have to be closely monitored for a while to see if the warfarin dosage has to be adjusted.

Possible side effects of blood thinners (especially if INR is too high) are easy bruising, bleeding from the gums or nose or prolonged bleeding from a cut. Any indication of bleeding in the gut is an emergency. Be careful with sharp tools, use waxed dental floss and a soft toothbrush, and don’t go barefoot.

Antiplatelet medications are blood thinners that work differently from anticoagulants. When you have a cut, blood cells called platelets clump together to stop the bleeding - but if they clump in a blood vessel they can cause a heart attack or stroke. Antiplatelet drugs keep the platelets from clumping together. Most of the precautions and side effects listed for warfarin also apply to antiplatelets.

Aspirin is an antiplatelet used by patients who are at high risk for heart attack or have already had one. A “baby” aspirin, 81 mg, is enough. Enteric coated aspirin passes through the stomach and dissolves in the intestine; buffered aspirin contains an antacid; they’re gentler on the stomach than plain aspirin. Aspirin that smells of vinegar has gone bad; don’t use it.

NSAIDs like Motrin or Advil interfere with aspirin. Take them eight hours before or after aspirin, or better, use acetaminophen (Tylenol) for aches.

Plavix and Effient are also antiplatelet drugs, but their mechanism is different from aspirin. Proton pump inhibitors (sometimes used to protect the stomach against aspirin) may interfere with Plavix - the studies aren’t definitive.

Fish oil (from eating fish or a supplement) is good for the heart, but it contains a blood thinner. If you take more than three grams a day you run a risk of bleeding.