What's New in the 5th Edition
"Low dose" and "high dose" replace the old "prophylactic" and "therapeutic" language.
New: a drug level can clear a block on its own. DOAC under 30 ng/mL, or anti-Xa activity 0.1 IU/mL or less, is acceptable regardless of time elapsed.
New antiplatelet hold time: ticagrelor (a P2Y12 inhibitor, not a DOAC) is now 5 days, down from the prior 5 to 7 day range.
Reversal agents (andexanet alfa, idarucizumab, PCC) are explicitly not for enabling a block in routine patients. Same goal either way: full clotting recovery before the needle.
First Principles
Spinal hematoma is rare, but catastrophic in a fixed, closed space, the epidural space has nowhere for a bleed to expand except onto the cord.
ASRA stays deliberately "antihemorrhagic": the aim is full hemostasis, not a convenient compromise.
Deep plexus and deep peripheral blocks follow the same rules as neuraxial blocks. This is not just a spine issue.
Aspirin or NSAIDs alone: no restriction, proceed.
Most DOAC-specific advice remains grade 2C, "we suggest." Judgment still matters; these are not hard stops.
DOACs: When to Stop
Before a neuraxial or deep block.
| Drug | High dose | Low dose |
|---|---|---|
| Apixaban | 72 h | 36 h |
| Rivaroxaban | 72 h | 24 h (30 h if CrCl <30) |
| Edoxaban | 72 h | No approved low dose |
| Dabigatran | 72 h (120 h if CrCl 30-49) | 48 h |
DOACs: Levels & Restart
Can't wait? A residual level can clear the block on its own: under 30 ng/mL, or anti-Xa 0.1 IU/mL or less.
PT and aPTT do not rule out a DOAC effect. These are the wrong tests for this question; don't let a normal PT/aPTT create false reassurance.
Restart low dose (prophylaxis): about 6 hours after the procedure.
Restart high dose: 24 hours or more, 48 to 72 hours after high-bleed-risk surgery.
High-dose DOAC: remove the needle or catheter 24 hours before the next dose, not after.
Unfractionated Heparin
IV heparin: stop 4 to 6 hours, with normal coags confirmed, before the block.
Give IV heparin no sooner than 1 hour after needle placement.
Low-dose SC (5,000 U): wait 4 to 6 hours, or confirm normal coags.
High-dose SC: 12 hours (up to 20,000 U/day) or 24 hours (over 20,000 U/day), plus a normal aPTT.
On UFH for more than 4 days? Check platelets first. Heparin-induced thrombocytopenia risk rises with duration of exposure.
LMW Heparin
Low (prophylactic) dose: wait 12 hours before the block.
High (therapeutic) dose: wait 24 hours before the block.
Restart prophylaxis: 4 hours or more after catheter removal.
Restart therapeutic: 24 hours, or 48 to 72 hours after high-bleed surgery.
On LMWH for more than 4 days, check platelets. CrCl under 30: double the wait times above.
Antiplatelets: Stop Times
| Agent | Stop time |
|---|---|
| Aspirin / NSAIDs | No wait, proceed |
| Clopidogrel | 5 to 7 days |
| Prasugrel | 7 to 10 days |
| Ticagrelor | 5 days |
| Cangrelor | 3 hours |
| Cilostazol | 2 days |
| GP IIb/IIIa (eptifibatide, tirofiban) | 4 to 8 hours |
| GP IIb/IIIa (abciximab) | 24 to 48 hours |
Warfarin, Fondaparinux, Lytics
Warfarin: stop 5 or more days, with a normalized INR. Remove the catheter once INR is under 1.5.
Fondaparinux, low dose (2.5 mg): 36 to 42 hours (58 hours if CrCl 30 to 50, avoid entirely if under 30).
Fondaparinux, high dose (5 to 10 mg): 70 hours in younger patients, 105 hours in the elderly.
Thrombolytics: avoid the needle for 48 hours or more, and confirm normal clotting including fibrinogen before proceeding.
Herbal supplements (garlic, ginkgo, ginseng) do not need to be stopped for a block.
Quick Card & Primary Sources
| Drug class | Key number to remember |
|---|---|
| Apixaban / rivaroxaban / edoxaban, high dose | 72 h |
| Dabigatran, high dose | 72 h (120 h if CrCl 30-49) |
| Any DOAC, residual level check | <30 ng/mL or anti-Xa ≤0.1 IU/mL clears the block |
| Warfarin | 5+ days, INR <1.5 |
| UFH IV | 4-6 h + normal coags |
| LMWH high dose | 24 h |
| Clopidogrel / ticagrelor / prasugrel | 5-7 / 5 / 7-10 days |
| Reversal agents for enabling a block | Not recommended, routine patients |
Primary sources checked for this guide:
- Kopp SL, Vandermeulen E, McBane RD, et al. Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy, 5th Edition. ASRA Pain Medicine, 2025.
- ASRA Pain Medicine Anticoagulation PBLD: Regional Anesthesia and Pain Procedures in Anticoagulated Patients. asra.com, September 2025.
- Guideline Central. ASRA Guidelines for Regional Anesthesia with Antithrombotic or Thrombolytic Therapy, 5th Edition, Guideline Summary.
- Direct oral anticoagulant management for neuraxial anaesthesia and deep peripheral nerve blocks. British Journal of Anaesthesia, 2025.
- Block and Load: The ASRA's Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy, 5th edition. ESRA newsletter, April 2025.