Are the Blood Thinners Advertised on TV Really Better?

Paralysis from stroke is a devastating disability commonly caused by blood clots blocking an artery in the brain. Warfarin (Coumadin) was the standard treatment used to prevent or treat these strokes as well as another problem in the deep leg veins (deep vein thrombosis or DVT).  Now we are bombarded by commercials for new blood thinners promoted by famous people like Arnold Palmer. Are these newer medications really better?

In 1933, we had no effective blood thinners. This was the year a Wisconsin farmer, Ed Carlson, brought Dr. Karl Paul Link blood from one of his cows that had bled to death from eating moldy sweet clover. Dr. Link noticed that the blood had not clotted. This led to several years of research to determine why the blood had not clotted. In 1939, the chemical thinning the blood was isolated, dicoumarol. Dicoumarol was soon used for rat poison. In 1954, a “newer, safer” version of dicoumarol called warfarin (generic name) or Coumadin (brand name) was introduced for people.

Warfarin is highly effective. For example, it reduces the approximately 5 percent per year risk of blood clot stroke from atrial fibrillation by about two thirds. Warfarin costs as little as $4 a month.  The main risk of warfarin is bleeding. Some bleeding occurs in about 7.2 percent of patients a year. The risk of serious disability or dying each year from warfarin is about 0.3 percent. Other disadvantages of warfarin are requiring blood tests, usually at least once a month, and difficulty getting exactly the right dose. Too little warfarin increases the risk of clots and too much increases the risk of bleeding.

Given the disadvantages of warfarin, four new medications are now available to prevent blood clots. These new medications are Apixaban  (Eliquis), costing $366 a month; dabigatran (Pradaxa), costing $356 a month; edoxaban (Savaysa), costing $298 a month; and rivaroxaban (Xarelto), costing $366 a month. Are these much more expensive medications worth the extra cost?

Unlike warfarin, the four new medications do not require blood tests to adjust their doses. All four have the disadvantage of causing bleeding. Warfarin is taken once a day. All the new medications except rivaroxaban (Xarelto) are usually taken twice a day.  Rivaroxaban (Xarelto) is often prescribed with food to improve absorption. Warfarin and all the other new medications may be taken with or without food.

Unfortunately, all of the large studies for these medications compare them with warfarin, and there are no good studies comparing them with each other. To help decide this, experts combine the data from different studies together for analysis. This is called meta-analysis. This type of analysis is not considered as good as one larger study because the design of each of the studies being analyzed is different.

The meta-analysis studies indicate that for stroke prevention patients on the new medications have fewer new strokes caused by bleeding than warfarin, and they live longer. For treatment of deep vein thrombosis, the new medications have similar outcomes to warfarin.

Overall, the new medications are more convenient for patients to take, have a lower risk of a stroke due to reduced bleeding in the brain and patients live longer. If you only looked at these factors, few patients would be taking warfarin. Unfortunately, many insurance companies are reluctant to routinely pay the huge difference in price between warfarin and the new medications. When pricing is looked at, a medication that costs $366 in the United States is available for as little as $80 in Canada. Is warfarin being used more than is ideal because insurance companies refuse to pay the cost or because pharmaceutical companies do not have competitive pricing? You decide.

Key References

1. Commercial with Arnold Palmer: https://www.ispot.tv/ad/AYGi/xarelto-game-plan-feat-chris-bosh-arnold-palmer-brian-vickers
2. Meek, T: This month in 1939: How dead cattle led to the discovery of warfarin. PMLive. June 27, 2013: http://www.pmlive.com/pharma_news/how_dead_cattle_led_to_the_discovery_of_warfarin_485464
3. Pirmohamed M: Warfarin: almost 60 years old and still causing problems. Br J Clin Pharmacol. 2006 Nov; 62(5): 509–511
4. GoodRx site for drug prices: https://www.goodrx.com/
5. Manning WJ, Singer DE, Lip GY. Atrial Fibrillation: Anticoagulant therapy to prevent embolization. Uptodate: https://www.uptodate.com/contents/atrial-fibrillation-anticoagulant-therapy-to-prevent-embolization
6. Pharmacy Checker. Prices in other countries: https://www.pharmacychecker.com/brand/price-comparison/xarelto/20+mg/