Key takeaways
- Current UK guidance is to continue most blood thinners for Mohs surgery, not stop them, because the clot or stroke risk from stopping usually outweighs the inconvenience of extra bleeding
- Warfarin, DOACs such as apixaban and rivaroxaban, and antiplatelets such as aspirin and clopidogrel are each managed slightly differently, and none should be stopped without discussing it first
- What usually changes is the anaesthetic technique and the closure method, not whether your medication continues
- Stopping is only considered for higher-bleeding-risk procedures, and only after weighing your personal clot risk against that benefit
- Never adjust or stop a blood thinner yourself. The decision involves your surgeon and the doctor who prescribes it
If you take a blood thinner, Mohs surgery can sound more complicated than it needs to be. Many patients assume they will have to come off their medication before a procedure like this, and are surprised to hear that is rarely the case.
Here is what actually tends to change, what stays the same, and why the advice has shifted away from automatically stopping these medications.
Why Blood Thinners Matter Before Mohs Surgery
Warfarin, DOACs, and antiplatelet drugs all work by making your blood less likely to clot, which is exactly why they were prescribed in the first place. During surgery, that same effect means more oozing and a slightly higher chance of bruising or a haematoma afterwards.
That sounds like a reason to stop them, and for many years it often was the default approach. The thinking on this has changed significantly over the past decade.
The Current Guidance: Continue, Don’t Stop
The British Society for Dermatological Surgery’s guidance on antithrombotics and skin surgery is clear: most of these medications should be continued for most skin surgery, Mohs surgery included.
The reasoning is straightforward. Bleeding after skin surgery is usually inconvenient, and rarely serious. Stopping a blood thinner, on the other hand, carries a real risk of stroke, a blood clot, or a heart attack, which is a far more serious trade-off.
Stopping is reserved for specific situations where the bleeding risk of the planned procedure is genuinely high and the clotting risk from pausing the medication is genuinely low, decided case by case rather than as a blanket rule.
What About Warfarin?
Warfarin is usually continued. Current guidance says stopping it is rarely justified, provided your INR, the blood test that measures how thin your blood is, sits below around 3.5.
You will typically need an INR check in the days before surgery. North Bristol NHS Trust’s Mohs surgery patient information asks patients to have this test five working days beforehand and bring the result along.
If your INR comes back outside the expected range, your team will usually contact your GP or anticoagulation clinic to adjust the dose, rather than cancelling your surgery outright.
What About DOACs Like Apixaban and Rivaroxaban?
For a standard Mohs closure, DOACs such as apixaban, rivaroxaban, and dabigatran are usually continued without interruption.
Where the bleeding risk is less clear, for example if a more complex reconstruction looks likely, and your underlying clot risk is lower, a short pause of 24 to 48 hours before surgery is sometimes considered, timed around your kidney function and restarted once the wound is secure.
For patients at genuinely high risk of a clot, such as those with a mechanical heart valve or a recent clot themselves, these drugs are generally kept going regardless, unless the prescribing doctor agrees otherwise.
What About Aspirin and Clopidogrel?
Low-dose aspirin, typically 75mg, carries a relatively small bleeding risk and is almost always continued. Stopping it is only really considered when there is no clear medical reason for taking it in the first place.
Clopidogrel tends to cause more prolonged oozing than aspirin, so for a higher-bleeding-risk procedure your surgeon may discuss postponing until it can be safely paused, usually in consultation with whoever prescribed it.
Guy’s and St Thomas’ NHS Foundation Trust’s patient information on Mohs surgery covers this same point: tell the team about any of these medicines in advance, and let them decide whether anything needs to change.
When Stopping Might Still Be Considered
Procedures carrying a higher bleeding risk, such as a skin flap, a graft, or a wound left to heal by secondary intention, are where stopping a medication becomes a genuine discussion rather than a default.
Patients on more than one blood thinner together, such as dual antiplatelet therapy after a cardiac stent, fall into this category too. Here, the safer path is often to delay surgery until a single medication is enough, rather than stopping either drug outright.
What Actually Changes About the Procedure
This is usually the real answer to what changes: not your medication, but your surgeon’s technique. The local anaesthetic formulation and injection approach can be adjusted specifically to help with bleeding control.
Our guide to local anaesthesia in Mohs surgery goes into this in more detail, including why stopping anticoagulants is rarely necessary once this is accounted for.
For a higher-risk case, your team may also plan for a firmer pressure dressing, a longer period of observation after your local anaesthetic wears off, or occasionally an agent called tranexamic acid to help control bleeding.
Who Makes the Decision
This is never a decision for you to make alone, and it is not one Miss Nayar makes alone either. It is a shared decision between your surgeon and the doctor who originally prescribed your blood thinner.
That might be your GP, a cardiologist, or an anticoagulation clinic, depending on why you take it. Your surgical team will usually liaise with them directly if any change is being considered.
What to Do Before Your Appointment
Keep taking your blood thinner as prescribed, and never stop or adjust the dose on your own in advance of surgery, even if you are anxious about bleeding.
Bring a complete list of everything you take, prescribed and over the counter, to your first visit, and arrange any INR test your team asks for in good time before the day itself.
Our guide to what Mohs micrographic surgery involves covers the wider preparation steps, and is worth reading alongside this one.
FAQ
Will I need to stop my blood thinner before Mohs surgery?
In most cases, no. Current guidance favours continuing most blood thinners for standard Mohs surgery. Stopping is only considered for specific, higher-bleeding-risk situations.
What happens if I stop my medication without telling anyone?
This can raise your risk of a stroke or blood clot without any clinical benefit, since the decision needs to weigh your specific bleeding and clotting risk together. Always discuss it with your team first.
Will I bruise more if I stay on my blood thinner?
Some extra bruising or oozing is possible, but it is usually manageable with pressure and good wound care, and is considered a reasonable trade-off against stopping the medication.
Do I need an INR test if I’m not on warfarin?
No, an INR test is specific to warfarin. If you take a DOAC or an antiplatelet drug instead, this test is not relevant to your care.
Recommended next step
If you take a blood thinner and have an upcoming skin cancer diagnosis, find out more about Miss Rakhee Nayar and how a dual-trained Mohs surgeon plans around medications like yours.
This article is for general information and does not replace a face-to-face medical assessment. Never stop or adjust any medication without first discussing it with your doctor.
Filed under Mohs Surgery
