Emergency extraction in a patient taking warfarin who is also self-medicating with an NSAID
A 64-year-old man attends as an emergency with severe spontaneous pain of five days' duration from the lower right first molar. The tooth is tender to percussion, has a 6 mm pocket on the distobuccal aspect and a periapical radiolucency. He has permanent atrial fibrillation and takes warfarin 5 mg daily; the INR taken at the anticoagulation clinic this morning is 3.4. Other medication: bisoprolol 5 mg and atorvastatin 20 mg. Four days ago he started ibuprofen 400 mg three times daily for the pain and is still taking it. He reports a penicillin allergy (rash as a child). There is no swelling, trismus or pyrexia. He asks you to 'take the tooth out now'.
1. Which features of this presentation would make you pause before extracting today, and how would you manage his pain in the interim?
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Points that must be addressed before the forceps come out
- An INR of 3.4 is above the usual therapeutic range (2.0-3.0 for AF) and, more importantly, is a moving target. A single morning value taken elsewhere should not be assumed to reflect the value at the time of surgery; the decision should be based on an INR taken within 24-72 hours of the procedure, and you should confirm it with the anticoagulation service rather than adjust warfarin yourself. A simple extraction at an INR of 3.4 is generally acceptable with local haemostatic measures, but a value >4.0 (or any value the local protocol sets) means deferral and liaison with the anticoagulation clinic. Never stop or alter warfarin without that liaison.
- He is taking ibuprofen with warfarin. This is both a pharmacodynamic (platelet inhibition, gastric erosion) and pharmacokinetic problem, and it raises bleeding risk for the extraction. Advise stopping it.
- This is a painful but localised problem. No swelling, trismus or pyrexia means there is no systemic spread, so the urgency is pain control and removal of the source, not antibiotics.
Interim management
- Stop the ibuprofen and substitute paracetamol 1 g four times daily (maximum 4 g/24 h), checking he is not already taking a paracetamol-containing compound.
- Consider a short course of a weak opioid only if paracetamol is insufficient, with awareness of constipation and falls risk.
- If the tooth is restorable and he prefers, extirpation or pulpotomy under local anaesthesia is a legitimate way to buy time and relieve pain.
- If extraction is to proceed, plan it as a single, unhurried appointment early in the week, with a verified recent INR and haemostatic materials available.
2. He returns three days later with a buccal swelling, trismus and a temperature of 38.2 degrees. What antibiotic would you consider, and what must be checked before you prescribe it?
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First: is an antibiotic the main treatment? No. A spreading infection with trismus and pyrexia needs removal of the source, so drainage and extraction (or at least incision of a collection) take priority; antibiotics are an adjunct. Do not let the prescription delay definitive treatment, and consider same-day referral if the swelling involves the buccal or submandibular spaces or he has difficulty swallowing.
Choosing the drug
- Penicillin allergy with a childhood rash only: this is not necessarily a true IgE-mediated allergy, but you cannot verify that in an emergency, so avoid penicillins.
- Metronidazole would normally be an obvious choice for a dental abscess, but it inhibits CYP2C9 and reliably potentiates warfarin, raising the INR and the bleeding risk. It is a genuine interaction, not a theoretical one.
- Clarithromycin or erythromycin are also CYP3A4 inhibitors and potentiate warfarin similarly, so they are no safer.
- Clindamycin has no significant warfarin interaction and covers the relevant anaerobes, but carries a real Clostridioides difficile risk and is reserved for genuine need.
Practical answer Check the current INR, involve the anticoagulation service, and if an antibiotic is genuinely indicated use clindamycin (or an agent agreed with the anticoagulation team and local micro guide) with explicit advice to report bleeding or bruising. Review at 24-48 hours and document the interaction reasoning, since the next prescriber will need it.
3. If you decide to extract today, describe your local anaesthetic and haemostatic plan, justifying each element.
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Local anaesthesia
- Inferior alveolar nerve block plus long buccal infiltration using articaine 4% with adrenaline 1:100,000 or lidocaine 2% with adrenaline 1:80,000. The vasoconstrictor is not contraindicated here: bisoprolol is cardioselective and a small dose of adrenaline in a healthy-compartment injection is safe; avoiding all vasoconstrictor would produce poorer anaesthesia and a more stressful, and therefore more cardiovascularly demanding, appointment.
- Aspirate in two planes for the block; a positive aspiration means repositioning, not injecting.
- Slow injection and a limited volume reduce peak plasma adrenaline and the risk of a pressure-related haematoma, which matters in an anticoagulated patient.
Haemostasis
- Atraumatic extraction, with a forceps or periotome rather than a flap where possible - minimise the wound.
- Curette the socket gently and remove granulation tissue; then suture (interrupted or figure-of-eight) to approximate soft tissue and hold a pack in place.
- Local measures: oxidised cellulose or a collagen sponge in the socket, plus pressure with a gauze pack for at least 10-20 minutes, given verbally and in writing.
- Prescribe tranexamic acid 4.8% mouthwash - rinse gently four times daily for two days - rather than systemic antifibrinolytics.
- Written advice: no rinsing, spitting, smoking or hot drinks for 24 hours; contact details if bleeding restarts.
Follow-up: review or telephone at 24-48 hours; warn about the interaction risk if any new drug is prescribed by anyone else.