Blood Thinners (Warfarin, Eliquis, Xarelto): The Mississippi Patient's Safety Guide

The categories

Warfarin (Coumadin, Jantoven)

The oldest oral anticoagulant. Works by interfering with vitamin K dependent clotting factors. Requires regular INR monitoring. Affected by many foods, medications, and supplements. Inexpensive but logistically complex.

Direct oral anticoagulants (DOACs)

Apixaban (Eliquis), rivaroxaban (Xarelto), edoxaban (Savaysa), dabigatran (Pradaxa). Newer category. Work directly on specific clotting factors. Do not require regular INR monitoring. Fewer food interactions than warfarin. More expensive. Have largely replaced warfarin for many indications but not all.

Antiplatelets

Technically a different category but often included in blood thinner conversations. Low dose aspirin (81 mg), clopidogrel (Plavix), prasugrel (Effient), ticagrelor (Brilinta). Affect platelet function rather than clotting factors. Used for cardiovascular indications including after stents and after heart attacks.

Injectable anticoagulants

Heparin, enoxaparin (Lovenox), fondaparinux. Used in hospital settings and sometimes at home for specific situations.

What blood thinners do and do not do

Blood thinners do not actually thin the blood. The blood is the same viscosity it was before. What they do is slow the formation of clots. This is essential for patients at risk of stroke from atrial fibrillation, after deep vein thrombosis or pulmonary embolism, in some heart valve conditions, and in several other situations. The trade off is that bleeding from any cause takes longer to stop.

The bleeding risk

Every blood thinner increases bleeding risk. Most bleeding episodes are minor (nosebleeds, bruising, longer than usual bleeding from small cuts). A smaller number are major (GI bleeding, intracranial hemorrhage, retroperitoneal bleeding). Recognizing serious bleeding signs early matters.

Signs of serious bleeding to know:

• Black, tarry stools or visible blood in the stool.
• Blood in vomit or coffee ground appearing vomit.
• Severe headache, particularly new, severe, or following head injury.
• Significant change in mental status, weakness on one side, vision changes, or speech changes.
• Excessive or prolonged bleeding from a wound.
• Bleeding gums that will not stop.
• Heavy menstrual bleeding much beyond your normal pattern.
• Bruising that appears without obvious cause and grows.
• Lightheadedness, pale skin, rapid heart rate.

Any of these in a patient on a blood thinner warrants immediate medical attention.

Medications and supplements that increase bleeding risk

• NSAIDs (ibuprofen, naproxen, aspirin at higher doses) significantly raise bleeding risk when combined with anticoagulants. Use acetaminophen for pain.
• Many antibiotics raise INR for warfarin patients and may increase bleeding risk with DOACs.
• Several antifungals.
• Many antidepressants, particularly SSRIs and SNRIs.
• Garlic, ginger, ginkgo, ginseng supplements (the four Gs).
• High dose fish oil.
• Vitamin E at high doses.
• Turmeric and curcumin at supplemental doses.
• St. John’s Wort affects warfarin levels.

Warfarin specifically

Warfarin requires more management than DOACs but is still used for specific indications including mechanical heart valves, certain renal situations, and others. If you are on warfarin:

• Get your INR checked as scheduled. The clinic, anticoagulation clinic, or your pharmacy point of care testing can help.
• Keep vitamin K intake consistent. Leafy greens and certain other foods are high in vitamin K. You do not need to avoid them; you need to eat them consistently rather than starting or stopping a large amount suddenly.
• Limit alcohol significantly.
• Use one pharmacy that handles all your prescriptions, so warfarin can be reviewed against everything else.
• Carry medical identification or a card noting that you are on warfarin.

DOACs specifically

Apixaban (Eliquis) and rivaroxaban (Xarelto) are the most commonly prescribed. Several considerations:

• Apixaban is twice daily. Rivaroxaban is once daily for most indications.
• Rivaroxaban should be taken with food at the higher doses used for atrial fibrillation and DVT/PE treatment.
• Kidney function affects appropriate dosing for both apixaban and rivaroxaban. The dose may need adjustment over time.
• DOACs do not require INR monitoring but kidney function and complete blood count should still be monitored.
• Apixaban can be opened and the contents mixed with food or given through a feeding tube for some patients. Rivaroxaban tablets can be crushed if needed.
• Reversal agents exist for both warfarin and the DOACs. Andexanet alfa for apixaban and rivaroxaban. Idarucizumab for dabigatran. Vitamin K and prothrombin complex concentrates for warfarin.

Procedures and surgery

Most procedures require some adjustment of blood thinner therapy. For warfarin, the medication is typically held for several days before the procedure with bridging anticoagulation in some cases. For DOACs, holds are typically shorter (1 to 2 days for most procedures) but the timing depends on the procedure and kidney function. Never stop your blood thinner on your own. Always coordinate with the prescriber and the procedure team.

Where pharmacy fits

Free medication therapy management for blood thinner patients. Every new prescription, every OTC purchase, every supplement gets a review. Serving Hattiesburg, the Pine Belt, Central Mississippi, and South Mississippi.

When to call a pharmacist

• You are starting a blood thinner for the first time.
• You are starting any new medication while on a blood thinner.
• You are considering an OTC medication or supplement.
• You have a planned procedure or surgery.
• You missed a dose.
• You have any concerning bleeding signs.
• Your kidney function has changed.

This article is for general information only and is not a substitute for personalized medical advice. Before starting or changing any medication, including over the counter products and supplements, talk with your pharmacist or physician about your specific situation.