Anticoagulant

[37] The bleeding risk depends on the class of anticoagulant agent used, the patient's age, and pre-existing health conditions.

[38] Newer non-vitamin K antagonist oral anticoagulants appear to have fewer life-threatening bleeding events than warfarin.

[43] In people with cancer, a systematic review has found warfarin had no effect on death rate or the risk of blood clots.

[39] Nonhemorrhagic adverse events of warfarin include skin necrosis, limb gangrene, and purple toe syndrome.

[59] Foods and food supplements with blood-thinning effects include nattokinase, lumbrokinase, beer, bilberry, celery, cranberries, fish oil, garlic, ginger, ginkgo, ginseng, green tea, horse chestnut, licorice, niacin, onion, papaya, pomegranate, red clover, soybean, St. John's wort, turmeric, wheatgrass, and willow bark.

A prominent member of this class, warfarin (Coumadin), was found to be the anticoagulant most prescribed in a large multispecialty practice.

[84] UFH binds to the enzyme inhibitor antithrombin III (AT), causing a conformational change that results in its activation.

[83] LMWH exhibits a higher anti-Xa/anti-IIa activity ratio and is useful as it does not require monitoring of the APTT coagulation parameter and has fewer side effects.

Betrixaban is significant as it was in 2018, the only oral factor Xa inhibitor approved by the FDA for use in acutely medically ill patients.

[96] Darexaban development was discontinued in September 2011; in a trial for prevention of recurrences of myocardial infarction in addition to dual antiplatelet therapy (DAPT), the drug did not demonstrate effectiveness, and the risk of bleeding was increased by approximately 300%.

[97] The development of letaxaban for acute coronary syndrome was discontinued in May 2011 following negative results from a Phase II study.

An oral direct thrombin inhibitor, ximelagatran (Exanta), was denied approval by the Food and Drug Administration (FDA) in September 2004[100] and was pulled from the market entirely in February 2006 after reports of severe liver damage and heart attacks.

[102] However, with regards to DOACs and invasive dental treatments, there has not been enough clinical evidence and experience to prove any reliable adverse effects, relevance or interaction between these two.

[103] Further clinical prospective studies on DOACs are required to investigate the bleeding risk and hemostasis associated with surgical and dental procedures.

[105] With low-bleeding-risk dental procedures, it is recommended that DOACs be continued by the patient to avoid any increase in the risk of a thromboembolic event.

[112] Reversal agents for warfarin are more widely studied, and established guidelines for reversal exist due to a longer history of use of warfarin and the ability to get a more accurate measurement of anticoagulation effect in a patient via measuring the INR (International Normalized Ratio).

[115] Specifically with warfarin, four-factor PCC (4F-PCC) has been shown to have superior safety and mortality benefits compared to FPP in lowering INR levels.

[112] Although specific antidotes and reversal agents for DOACs are not as widely studied, idarucizumab (for dabigatran) and andexanet alfa (for factor Xa inhibitor) have been used in clinical settings with varying efficacy.

[120] Another drug called ciraparantag, a potential reversal agent for direct factor Xa inhibitors, is still under investigation.

Dental practitioners play an important role in the early detection of anticoagulant overdose through oral manifestations, as the patient does not show any symptoms.

An International Normalised Ratio (INR) test would be recommended to confirm the overdose so that the dosage can be adjusted to an acceptable standard.

The INR test measures the time it takes for a clot to form in a blood sample relative to a standard.

For a patient who needs to undergo dental treatments which are more likely to cause bleeding, such as simple tooth extractions (1-3 teeth with small wound size), drainage of swelling inside the mouth, periodontal charting, root planing,  direct or indirect filling which extends below the gingiva, complex filling, flap raising procedure, gingival recontouring and biopsies, the dentist needs to take extra precautions apart from the standard procedure.

The recommendations[127] are as follows: There is general agreement that in most cases, treatment regimens with older anticoagulants (e.g., warfarin) and antiplatelet agents (e.g., clopidogrel, ticlopidine, prasugrel, ticagrelor, and/or aspirin) should not be altered before dental procedures.

The risks of stopping or reducing these medication regimens (i.e., thromboembolism, stroke, myocardial infarction) far outweigh the consequences of prolonged bleeding, which can be controlled with local measures.

In patients with other existing medical conditions that can increase the risk of prolonged bleeding after dental treatment or receiving other therapy that can increase bleeding risk, dental practitioners may wish to consult the patient's physician to determine whether care can safely be delivered in a primary care office.

Based on limited evidence, the consensus appears to be that in most patients who are receiving the newer direct-acting oral anticoagulants (i.e., dabigatran, rivaroxaban, apixaban, or edoxaban) and undergoing dental treatment (in conjunction with usual local measures to control bleeding), no change to the anticoagulant regimen is required.

[128] As of November 2021[update], the direct factor XIa inhibitor milvexian is in Phase II clinical trials for the prevention of an embolism after surgery.