Anticoagulants

Anticoagulants are chemicals that prevent or reduce the blood's ability to clot. They do this by interrupting or preventing the coagulation of blood cells. As medication, anticoagulants are given for numerous purposes, including the prevention or treatment of heart attacks, stroke, or other thrombotic disorders that result in the restriction of blood flow. In nature, anticoagulants are present in haemovores (i.e. an animal that primarily feeds on blood) such as leeches.

Anticoagulants

• Coumarins
• Heparin and derivative substances
• Synthetic pentasaccharide inhibitors of factor Xa (fondaparinux, idraparinux, idrabiotaparinux)
• Directly acting oral anticoagulants (Xa inhibitors rivaroxaban, apixaban, edoxaban, betrixaban),  are in current use.   Direct thrombin inhibitors (hirudin, lepirudin, bialirudin, argatroban, dabigatran) are expected to replace heparin but are not in widespread use. 
• Antithrombin protein therapeutics
• Novel anticoagulants

Antiplatlet drugs

Note about dual antiplatlet therapy: Patients are often prescribed ASA plus a ADP/P2Y inhibitor.  This is referred to as dual antiplatelet therapy (DAPT).  

• Irreversible cycoloxygenase inhibitors (ASA)
• Adenosine diphosphate receptor inhibitors (Plavix, Brillanta, Ticlid)
• Phosphodiesterase inhibitors (Pletal)
• PAR-1 antagoists (Zontivity)
• IIB/IIIA inhibiros (IV only) (ReoPro, Integrillin, Aggrastat)
• Adenosine reuptake inhibitors (Persantine)
• Thromboxane inhibitors

Guidance from the Scottish Dental Society on low vs high risk procedures is included below.  In general, consult with the patients physician before stopping anticoagulation for high risk procedures and consider the use of local hemostatic measures such as Surgicel and/or gelfoam. 

In addition; consider use of Point of Care device to measure INR for patients who are on coumadin, and limiting dentoalveolar surgery to INR <3.0.  Antiplatlet medications may need to be stopped 7 days prior to surgery, and Xa anticoagulants 1-2 days prior in consultation with the patients physician. 

Table 1 Post-operative bleeding risks for dental procedures

1. Local anaesthesia should be delivered using an aspirating syringe and should indude a vasoconstrictor, unless contraindicated. Note that other methods of local anaesthetic delivery are preferred over regional nerve blocks, whether the patient is taking an anticoagulant or not.
2. There is no evidence to suggest that an inferior dental block performed on an anticoagulated patient poses a significant risk of bleeding. However, for patients taking warfarin, if there are any indications that the patient has an unstable INR (see Section 5), or other signs of excessive anticoagulation, an INR should be requested before the procedure. 
3. Although a BPE can result in some bleeding from gingival margins, this is extremely unlikely to lead 
   to complications. 
4. Simple extractions refers to those which are expected to be straightforward, without surgical complications. 
5. Complex extractions refers to those which may be likely to have surgical complications.