Drugs, targets and what to check
| Drug | Target | Lab or reversal | Dental approach |
|---|---|---|---|
| Warfarin | Vitamin K–dependent factors II, VII, IX, X (and proteins C and S) | INR (usual target 2–3; 2.5–3.5 for some mechanical valves); reversal vitamin K, prothrombin complex concentrate | Check INR within 24 h; most extractions are done without stopping if INR is in range (often quoted as up to 3.5), with local hemostasis |
| Dabigatran | Direct thrombin inhibitor | No routine test; idarucizumab reverses | Usually continue; for higher-risk surgery, the physician may advise timing or a skipped dose |
| Rivaroxaban, apixaban, edoxaban | Factor Xa inhibitors | No routine test; reversal options include andexanet alfa (check current availability) and PCC | Usually continue; schedule surgery late in the dosing interval when advised |
| Unfractionated heparin | Antithrombin → IIa and Xa | aPTT; protamine reverses | Hospital setting |
| Enoxaparin (LMWH) | Mainly Xa via antithrombin | Anti-Xa level; partial protamine reversal | Bridging therapy; consult the physician |
| Aspirin | Irreversible COX-1 (thromboxane A₂) | No routine test | Do not stop for routine dental surgery |
| Clopidogrel, prasugrel, ticagrelor | P2Y12 ADP receptor | No routine test | Never stop dual antiplatelet therapy after a stent without the cardiologist (stent thrombosis risk) |
Local hemostasis toolkit
- Firm pressure with gauze, atraumatic technique, sutures.
- Oxidized regenerated cellulose, absorbable gelatin sponge or collagen in the socket.
- Tranexamic acid mouthwash or soaked gauze (antifibrinolytic) after surgery in anticoagulated patients.
- Plan treatment early in the day and early in the week so bleeding problems can be managed.
Interactions that change bleeding risk
- Raise INR with warfarin: metronidazole, fluconazole and other azoles, erythromycin and clarithromycin, regular high-dose acetaminophen; many antibiotics modestly.
- Add bleeding risk by other routes: NSAIDs (platelets, GI ulcers), SSRIs, fish oil and ginkgo (supplements).
- Lower INR: rifampin, carbamazepine, vitamin K–rich diets.
- Platelet count: spontaneous bleeding is unlikely above about 50,000/µL; normal is about 150,000–450,000/µL.
⚠️ Common traps
- Stopping warfarin or a DOAC on your own before an extraction: decisions about interruption belong to the prescribing physician; usually they continue.
- Using INR to judge a DOAC: INR is not a reliable measure of DOAC effect.
- Prescribing metronidazole or fluconazole for a warfarin patient without considering INR.
- Telling a patient with a recent coronary stent to stop clopidogrel for a filling or extraction.
Mini-quiz
- A patient on warfarin needs two extractions. The INR measured this morning is 2.6. The usual approach is:
- Which drug is a direct thrombin inhibitor?
- Which antibiotic is most likely to raise INR in a patient taking warfarin?
- Clopidogrel works by blocking:
- Which local agent is an antifibrinolytic useful after extractions in anticoagulated patients?
Answer key: 1 D · 2 A · 3 C · 4 D · 5 B