Which nerve blocks are safe on anticoagulants?

ASRA treats deep plexus and deep peripheral blocks exactly like neuraxial — full timing intervals, same hold times. It does not subdivide the rest, which is the gap a separate advisory exists to fill.

Reviewed and updated September 2026 · Written by Anastasia Jackson, DNAP, CRNA

Every clinical claim on this page is cited to its source below. How we source clinical content — and the corrections we have made, with what each one was and why it changed.

There is no single answer, because "peripheral nerve block" covers everything from an axillary block you could compress with a finger to a lumbar plexus block that can bleed into the retroperitoneum unnoticed. The useful framing is that the guideline handles the deep end explicitly and leaves the rest to judgment, and that the judgment reduces to three questions you can apply to any block, including ones no advisory has classified yet.

What ASRA actually says

The fifth edition of the ASRA evidence-based guidelines, published January 2025, is the current source.¹ Its position on peripheral techniques is narrow and specific: deep plexus and deep peripheral blocks are held to the same standard as neuraxial blocks. Paravertebral, lumbar plexus and lumbar sympathetic blocks fall inside that category, so a thoracic paravertebral requires the same adherence to hold intervals as epidural placement.^1,2

The accompanying editorial to the Tsui advisory makes the reasoning explicit. Hemorrhagic complications following deep plexus and deep peripheral techniques, particularly in the presence of antithrombotic therapy, are often serious and a source of major patient morbidity including death from massive bleeding.³

What changed in the fifth edition

Three shifts matter for block practice:^1,4

• Terminology. "Prophylactic" and "therapeutic" were replaced by low dose and high dose, aligning ASRA with the joint ESAIC/ESRA guidelines,¹⁷ which for their part state that these hold intervals do not apply to peripheral nerve blocks of low bleeding risk that are superficial and compressible.
• Drug-level thresholds. Residual apixaban, rivaroxaban or edoxaban below 30 ng/mL, or anti-factor Xa activity at or below 0.1 IU/mL, are acceptable before a neuraxial block, deep plexus block, or peripheral nerve block. This is a move away from purely time-based protocols toward pharmacokinetically informed decisions.
• Renal function. The guideline suggests not performing neuraxial or deep plexus/peripheral blocks in patients with severe renal impairment (creatinine clearance under 30 mL/min) on fondaparinux, given its 72-hour half-life.

The agent-by-agent table is longer than this and lives in the full guideline. The point to carry is structural: for anything ASRA classifies as deep, there is no separate, more permissive peripheral-block interval. You are working from the neuraxial column.

The Tsui tiers — everything ASRA does not classify

The Regional Anesthesia and Acute Pain Section of the Canadian Anesthesiologists' Society assembled seven experts to classify bleeding risk across peripheral nerve and interfascial plane blocks, producing a 2019 practice advisory.⁵ It exists in direct response to the perceived lack of risk stratification within ASRA guidance, and it is the document most clinicians are actually reaching for when the block in front of them is not a paravertebral.⁶

An umbrella review of systematic reviews adds texture in both directions: head and neck punctures generally do not produce bleeding complications, axillary brachial plexus blocks carry a minor hematoma incidence, and interscalene findings conflict — some reviews report hematoma and spinal injury, others classify it low risk. Abdominal wall blocks including transversus abdominis plane, ilioinguinal and rectus sheath blocks were reported to carry a higher hematoma risk than commonly assumed, and paravertebral and intercostal blocks were classified high risk.⁹ An expert panel consensus estimated the overall bleeding complication rate after peripheral nerve block in patients on antithrombotics at roughly 0.67% (95% CI 0.51–0.83).¹⁰

PENG, and why it is not in the advisory

The pericapsular nerve group block is absent from the Tsui advisory for a timing reason rather than a clinical judgment — the block was first described in 2018 and the advisory published in 2019. So it has to be reasoned from the framework rather than looked up.

On depth and compressibility it reasons toward intermediate or high, closer to lumbar plexus than to fascia iliaca despite sharing an anatomic neighborhood with the latter.

The reported experience is reassuring

A systematic overview covering 48 publications — 36 case reports or series and 12 letters, with no randomized trials identified at the time — found some cases of femoral and obturator nerve block but no major complication such as hematoma, bleeding, or needle-related organ injury reported.¹¹ StatPearls concurs that with ultrasound-guided administration the risk of femoral nerve or vascular damage with hematoma is minimal.¹² There is now published correspondence specifically titled "Pericapsular nerve group block in patients on antithrombotic drugs: a reply to ESAIC/ESRA guidelines," so the question is live in the literature rather than settled.¹³

The caveat that belongs alongside it

The practical position

Treat PENG as intermediate risk. Perform it under ultrasound with the vascular structures actively identified, and do not hold an anticoagulant purely to place it. In the anticoagulated hip fracture patient specifically, infrainguinal fascia iliaca has the better-established low-risk classification,^5,7 even though PENG has become the more popular block on analgesic efficacy and quadriceps-sparing grounds.

The three questions that transfer

New blocks are described faster than advisories can classify them. When the block in front of you is not in any table, these are what the frameworks reduce to:^5,8

1. How deep is it? Depth affects needle visibility and the volume of tissue a hematoma can occupy before anything is apparent.
2. Can you compress it? A site you can hold pressure on is a fundamentally different problem from one you cannot.
3. Would you know? If a hematoma formed, would it be visible, palpable, or would the first sign be hemodynamic hours later?

Proximity to critical structures and the consequence of mass effect are the fourth consideration folded into the ASRA survey scoring — the structured depth-compressibility-proximity approach that moved several blocks into a higher category than clinicians had initially assigned them.⁸

The point that is easy to skip

With rare exception, plexus, interfascial plane and peripheral nerve blocks are procedures used for analgesia rather than anesthesia, which makes them elective procedures intended to reduce pain, opioid use and opioid-related side effects. The editorialists put the consequence directly: the decision to hold an anticoagulant with the sole intent of placing an analgesic block is not one to make without collaboration with the cardiologist or primary care physician, because holding anticoagulation in certain patients may pose risks far greater than the bleeding risk of the block or of choosing a different analgesic approach.³

Tsui's group pushed back on that framing, noting that many peripheral blocks — brachial plexus blocks in particular — are now routinely used as the sole technique providing surgical anesthesia rather than as an analgesic add-on, so the "rare exception" characterization does not fit current practice.¹⁶ Both positions are reasonable. The distinction that resolves it in a given case is whether the block is the anesthetic or an adjunct to it.

Where this leaves you

The evidence base here is weak and largely consists of expert opinion. The advisory authors say so themselves, conceding that as new evidence emerges the stratification will need to be revisited and refined.¹⁶ A commentary reviewing the field described the advisory as providing expert-level opinion at best, given the weakness of the underlying evidence.⁶

That is not a reason to ignore it. It is a reason to hold the tiers loosely, apply the three questions when the tiers do not cover your block, and treat any decision to alter an anticoagulation regimen as a shared one rather than a regional anesthesia decision made alone.

Frequently asked questions

Which nerve blocks require the same anticoagulation hold as an epidural?

Deep plexus and deep peripheral blocks — paravertebral, lumbar plexus and lumbar sympathetic. ASRA holds these to the same standard as neuraxial techniques, so a thoracic paravertebral requires the same adherence to hold intervals as epidural placement.^1,2 The fifth edition states its intervals for "neuraxial block or deep plexus/peripheral block" as a single category, so there is no separate, more permissive peripheral interval for these blocks.

When should apixaban be stopped before an epidural or a deep block?

ASRA suggests high-dose apixaban be discontinued at least 72 hours before a neuraxial block or a deep plexus or peripheral block.¹ The fifth edition also introduced drug-level thresholds as an alternative to waiting: residual apixaban, rivaroxaban or edoxaban below 30 ng/mL, or anti-factor Xa activity at or below 0.1 IU/mL, is acceptable before neuraxial, deep plexus or peripheral nerve block.^1,4 That shift toward pharmacokinetically informed timing is one of the most significant changes in the 2025 edition.

Is a quadratus lumborum block low risk because it is an abdominal wall block?

No. The Tsui advisory classifies quadratus lumborum as high risk, judging its bleeding and visceral injury risk similar to a lumbar plexus block, while acknowledging sparse published data either way.⁵ It is frequently grouped with transversus abdominis plane blocks in teaching, which is where the misconception comes from.

Can I do a fascia iliaca block on an anticoagulated hip fracture patient?

Infrainguinal fascia iliaca is treated as a relatively low-risk block for bleeding complications by both the Canadian consensus and the 2013 UK guidance on regional anaesthesia in patients with abnormalities of coagulation.^5,6,7 It is the block with the best-established low-risk classification for this specific patient, which is worth weighing against newer alternatives that may have better analgesic profiles but less settled bleeding data.

Is a PENG block safe in a patient on anticoagulants?

PENG is not classified in the Tsui advisory, because the block was described in 2018 and the advisory published in 2019. Reasoning from the framework, it is deep, poorly compressible, and a bleed there would present as a falling hematocrit rather than anything visible — which argues for intermediate to high risk. A systematic overview of 48 publications reported no major hematoma, bleeding or needle-related organ injury,¹¹ but absence of reported complications in a young technique is weak evidence, and the corona mortis crosses the retropubic space behind the superior pubic ramus in a substantial proportion of people.^14,15 A reasonable position is to treat it as intermediate risk, use ultrasound with the vessels identified, and not hold an anticoagulant purely to place it.

Does an INR above 1.5 contraindicate a PENG block?

No — that figure is the neuraxial catheter removal threshold and does not transfer to a peripheral block. Applying neuraxial numbers to peripheral techniques is a common error. It can wrongly exclude a patient from a reasonable analgesic option, and it can create false reassurance that a number below the threshold makes a deep, non-compressible block safe.

Should I hold an anticoagulant just to place an analgesic block?

Not without involving the clinician managing the anticoagulation. The editorial accompanying the Tsui advisory states that holding an anticoagulant with the sole intent of placing an analgesic block is not a decision to make without collaboration with a cardiologist or primary care physician, because the thrombotic risk of holding may exceed the bleeding risk of the block or of simply using a different analgesic approach.³ The counterargument, from the advisory authors, is that many peripheral blocks are now the sole anesthetic rather than an analgesic add-on, which changes the calculus in those cases.¹⁶

How do I assess a block that no guideline has classified?

Three questions: how deep is it, can you compress it, and would you know if a hematoma formed. Proximity to critical structures and the consequence of mass effect are the fourth consideration. When clinicians applied a structured depth-compressibility-proximity score in an ASRA survey, several blocks — including erector spinae, infraclavicular, subgluteal sciatic and quadratus lumborum — moved into the high-risk category compared with their initial unaided assessments.⁸

References

1. Kopp SL, Vandermeulen E, McBane RD, Perlas A, Leffert L, Horlocker T. Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (fifth edition). Reg Anesth Pain Med. Published online 29 January 2025. doi:10.1136/rapm-2024-105766. PMID 39880411.
2. Horlocker TT, Vandermeuelen E, Kopp SL, Gogarten W, Leffert LR, Benzon HT. Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: ASRA Evidence-Based Guidelines (fourth edition). Reg Anesth Pain Med. 2018;43(3):263–309.
3. Horlocker TT, Neal JM, Kopp SL. Practice advisory on the bleeding risks for peripheral nerve and interfascial blockade: going out on a limb. Can J Anaesth. 2019. doi:10.1007/s12630-019-01467-9. Editorial. Source of the deep plexus morbidity statement, the presentation-as-blood-loss point, and the position on holding anticoagulants for analgesic blocks.
4. ESRA newsletter editors. Block and load: the ASRA's regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy, 5th edition. European Society of Regional Anaesthesia, 2025. Summary of the low-dose/high-dose terminology change, the drug-level thresholds, and the alignment with ESAIC/ESRA guidance.
5. Tsui BCH, Kirkham K, Kwofie MK, Tran DQ, Wong P, Chin KJ, Sondekoppam RV. Practice advisory on the bleeding risks for peripheral nerve and interfascial plane blockade: evidence review and expert consensus. Can J Anaesth. 2019;66(11):1356–1384. doi:10.1007/s12630-019-01466-w.
6. Regional anaesthesia in patients at risk of bleeding. BJA Educ. 2021. doi:10.1016/j.bjae.2020.09.005. Source of the characterization of the advisory as expert-level opinion and of the fascia iliaca position.
7. Harrop-Griffiths W, Cook T, Gill H, et al. Regional anaesthesia and patients with abnormalities of coagulation: the Association of Anaesthetists of Great Britain & Ireland, the Obstetric Anaesthetists' Association and Regional Anaesthesia UK. Anaesthesia. 2013;68:966–972.
8. Application of a systematic approach to score bleeding risk in regional anesthesia peripheral nerve block procedures. 44th Annual Regional Anesthesiology and Acute Pain Medicine Meeting, American Society of Regional Anesthesia and Pain Medicine, 2019. Fifteen regional anesthesiologists, 94% response rate; the depth-compressibility-proximity score.
9. Puncture site bleeding complications of peripheral nerve block in patients taking antithrombotic and anticoagulant drugs: an umbrella review. PMC11108675. Five systematic reviews synthesized qualitatively.
10. Peripheral nerve blocks in patients on antithrombotic drugs — a rescue or an unnecessary risk? Expert panel consensus classification of peripheral nerve blocks by potential for serious bleeding complications; estimated bleeding incidence 0.67% (95% CI 0.51–0.83).
11. Pericapsular nerve group block: an overview. Minerva Anestesiol. PMID 33432791. Forty-eight publications reviewed; no major hematoma, bleeding, or needle-related organ injury reported.
12. Pericapsular Nerve Group Block. StatPearls. NCBI Bookshelf NBK567757.
13. Pericapsular nerve group block in patients on antithrombotic drugs: a reply to ESAIC/ESRA guidelines. Correspondence.
14. Darmanis S, Lewis A, Mansoor A, Bircher M. Corona mortis: an anatomical study with clinical implications in approaches to the pelvis and acetabulum. Clin Anat. 2007;20(4):433–439. PMID 16944498. Forty cadavers, 80 hemipelvises; anastomosis in 83%, of which 60% exceeded 3 mm diameter; located 40–96 mm from the symphysis pubis.
15. Corona mortis. Radiopaedia reference article. Pooled prevalence across hemipelvises: venous 41.7%, arterial 17%, combined 49.3%.
16. Tsui BCH, Kirkham K, Kwofie MK, et al. Practice advisory on the bleeding risks for peripheral nerve and interfascial blockade: rooted in evidence. Can J Anaesth. 2019. doi:10.1007/s12630-019-01520-7. Authors' reply to the editorial.
17. Kietaibl S, Ferrandis R, Godier A, et al. Regional anaesthesia in patients on antithrombotic drugs: joint ESAIC/ESRA guidelines. Eur J Anaesthesiol. 2022. Notes that hold intervals do not apply to peripheral nerve blocks with low bleeding risk that are superficial and compressible.