Xarelto vs Warfrin

Xarelto vs Warfrin

Recently, various players in the pharmaceutical sector have introduced a brand new line of anticoagulant drugs (popularly called “blood thinners,” ) that have guaranteed to make life much easier for physicians who treat patients at risk for stroke. A stroke of course is the consequence of a blood clot that cuts off blood supply to the mind, and can lead to permanent injury and maybe even death.

For decades, the conventional medication used to prevent clotting was a type of rat poison called warfarin. It is derived from a material called coumarin, a biochemical seen in woodruff and sweet clover (which gives these plants their agreeable scent).

The Federal Drug Administration in 1954 approved the blood thinner warfarin to help lower the chance of blood clots leading to stroke for the more than 2 million Americans who have an abnormal heart rhythm called atrial fibrillation. For many years, warfarin (Coumadin) was the only medication available.

The drawback of Warfarin is that it needs constant patient monitoring, due to the variety of likely future interactions with other drugs too as certain foods (such as leafy greens, which include high rates of Vitamin K). By giving the patient high doses of Vitamin K., yet, hemorrhaging can be controlled easily

Advantage of using the brand new Factor Xa inhibitors as Xarelto is that there are relatively few interactions – and hence, less (expensive) patient observation is required.  If uncontrolled bleeding does occurs, there is absolutely no strategy to stop it – other than to place the patient on emergency dialysis to be able to get the drug out of the system as fast as possible. Even a slight bulge on the head can be deadly.

Here are the key differences between the two blood thinners that have become so popular.

1. Xarelto works otherwise. Patients need continuous testing to determine dosage, although with less vitamin K in circulation, blood takes more time to clot. Vitamin K doesn’t change, and continuous monitoring isn’t needed.

2. Dosage. For stroke risk reduction, the typical dose of Xarelto is 20 milligrams once a day, taken with the evening meal, based on WebMD. The optimal dosage of Warfarin can depend on diet, age and other drugs and varies from person to person. “The dosing is delicate,” said WebMD. “Give too much, and the risk of bleeding rises, sometimes alarmingly. Give too little, along with the stroke risk stays.”

3. Cost. Xarelto is more expensive for all those without insurance. But since insurance usually covers Xarelto, for those with coverage the price differences would be minimal. In some instances, the out-of-pocket price for Xarelto is lower than Warfarin.

4. Bleeding. Warfarin carries a risk of brain hemorrhage, which is uncommon but fatal. Although significant bleeding events occur less frequently when taking Xarelto than with warfarin, they could happen. Luckily the serum half-life of Xarelto is comparatively brief — five to nine hours — so its effect will vanish within about 24 hours.

5. Dietary issues. Patients on warfarin must get blood tests at least monthly and see their consumption of Vitamin K, a nutrient that could lessen the effectiveness of warfarin and can be found in leafy green vegetables like spinach, chard and kale. No dietary dilemmas are found with Xarelto.

6. Hips and knees. In studies on hip and knee replacement patients, those taking Xarelto were much less likely than those on other anti-clot therapies, including warfarin, to have clot issues, according to WebMD.

REFERENCES
[1]. FDA U.S. Food and Drug Administration Website: “MEDICATION GUIDE XARELTO® (zah-REL-toe) (rivaroxaban) tablets” Reference ID: 3688029 http://www.fda.gov/downloads/drugs/drugsafety/ucm280333.pdf (Accessed June 2015):

[2]. “Bleeding with dabigatran, rivaroxaban, apixaban. No antidote, and little clinical experience.” Prescrire Int. 2013 Jun;22(139):155-9.

[3]. Institute for Safe Medication Practices (ISMP) “ISMP List of High-Alert Medications in Acute Care Settings” https://www.ismp.org/tools/highalertmedications.pdf (Accessed June 2015)

[4]. Jaeger M, Jeanneret B, Schaeren S. “Spontaneous spinal epidural haematoma during Factor Xa inhibitor treatment (Rivaroxaban).” Eur Spine J. 2012 Jun;21 Suppl 4:S433-5.

[5]. Patel MR, Mahaffey KW, Garg J, et al; and the ROCKET AF Steering Committee, for the ROCKET AF Investigators. “Rivaroxaban versus warfarin in nonvalvular atrial fibrillation.” N Engl J Med. 2011;365(10):883-891.

[6]. J P Hanley “Warfarin reversal” J Clin Pathol. 2004 Nov; 57(11): 1132–1139.

[7]. Daniel S. Budnitz, M.D., M.P.H., Maribeth C. Lovegrove, M.P.H., Nadine Shehab, Pharm.D., M.P.H., and Chesley L. Richards, M.D., M.P.H. “Emergency Hospitalizations for Adverse Drug Events in Older Americans” N Engl J Med 2011; 365:2002-2012 November 24, 2011

[8]. Baglin TP, Keeling DM, Watson HG; British Committee for Standards in Haematology “Guidelines on oral anticoagulation (warfarin): third edition–2005 update.”. Br J Haematol. 2006 Feb;132(3):277-85.

[9]. Huffpost Healthy Living “FDA Advisers Review Clot Drug Xarelto” http://www.huffingtonpost.com/2011/09/08/fda-advisers-review-clot-drug-xarelto_n_954113.html Posted: 09/08/2011 (Accessed June 2015)

[10]. Bruce L. Davidson, Sara Verheijen, Anthonie W. A. Lensing, Martin Gebel, Timothy A. Brighton, Roger M. Lyons, Jeffrey Rehm, Martin H. Prins: “Bleeding Risk of Patients With Acute Venous Thromboembolism Taking Nonsteroidal Anti-Inflammatory Drugs or Aspirin.” JAMA Intern Med. 2014;174(6):947-953. doi:10.1001/jamainternmed.2014.946.

[11]. Raunsø J, Selmer C, Olesen JB, Charlot MG, Olsen AM, Bretler DM, Nielsen JD, Dominguez H, Gadsbøll N, Køber L, Gislason GH, Torp-Pedersen C, Hansen ML. “Increased short-term risk of thrombo-embolism or death after interruption of warfarin treatment in patients with atrial fibrillation”. Eur Heart J. 2012 Aug;33(15):1886-92.

[12]. Institute for Safe Medication Practices (ISMP) “QuarterWatch Monitoring FDA MedWatch Reports – Why Reports of Serious Adverse Drug Events Continue to Grow – October 3, 2012 – Data from 2012 Quarter 1” http://www.ismp.org/quarterwatch/pdfs/2012Q1.pdf (Accessed June 2015)

[13]. Food and Drug Administration Web site. “Adverse Event Reporting System (AERS). (2011)” http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Surveillance/AdverseDrugEffects/default.htm (Accessed  February 2011).

[14]. Institute for Safe Medication Practices (ISMP) “QuarterWatch Monitoring FDA MedWatch Reports – Anticoagulants the Leading Reported Drug Risk in 2011 – May 31, 2012 – New Data from 2011 Quarters 3 – 4http://www.ismp.org/quarterwatch/pdfs/2011Q4.pdf (Accessed June 2015)

[15]. Paul Harper, Laura Young, Eileen Merriman: “Bleeding Risk with Dabigatran in the Frail Elderly” N Engl J Med 2012; 366:864-866

[16]. Frank Siebelt, Jonathan Gould, William Hardy: “Bayer faces law suits in United States over Xarelto: paper”  http://www.reuters.com/article/2014/06/14/us-bayer-suit-idUSKBN0EP0HW20140614 Reuters website, June 14, 2014. (Accessed June 2015)

[17]. Hsien-Yen Chang, Meijia Zhou, Wenze Tang, G Caleb Alexander, Sonal Singh: “Risk of gastrointestinal bleeding associated with oral anticoagulants: population based retrospective cohort study” BMJ 2015;350:h1585