Peripheral nerve blocks (PNBs) are regional anesthetic techniques in which local anesthetics are injected near specific peripheral nerves to selectively block sensory and/or motor transmission within a defined anatomical region. In clinical practice, PNBs may be used as the primary anesthetic method for surgeries involving the upper or lower extremities, such as shoulder, arm, forearm, knee, or ankle procedures. Alternatively, they may serve as an adjunct to general anesthesia to enhance intraoperative and postoperative analgesia. They may also be utilized in the management of chronic pain syndromes. PNBs provide targeted, long-lasting pain control, which can reduce perioperative opioid use, minimize systemic adverse effects, and facilitate faster functional recovery. Nerve blocks can be stratified into superficial and deep blocks, with differing considerations, including when patients are on anti-coagulants.

PNBs are generally categorized as superficial or deep based on anatomical location and tissue compressibility. Superficial nerve blocks target nerves in relatively accessible areas surrounded by compressible tissue. Examples include femoral, interscalene, and axillary blocks. These blocks are easier to visualize with ultrasound and pose a lower risk of serious bleeding. Deep nerve blocks, such as lumbar plexus or paravertebral blocks, involve deeper, non-compressible tissue planes and are often performed in proximity to major vascular or neural structures. Due to this anatomical complexity, deep blocks are associated with a higher risk of bleeding and neurological complications in patients on anticoagulants, whereas superficial nerve blocks do not require the same caution (1).

Anticoagulants fall into three main categories: vitamin K antagonists (e.g., warfarin); parenteral agents, such as unfractionated heparin and low-molecular-weight heparin (LMWH); and direct oral anticoagulants (DOACs), including apixaban, rivaroxaban, and dabigatran. These medications prevent thromboembolic events, such as stroke, pulmonary embolism, and deep vein thrombosis.

Whether a PNB can be safely performed without interrupting anticoagulant therapy depends on the type of block and the specific pharmacologic agent. According to American Society of Regional Anesthesia (ASRA) guidelines, superficial blocks can generally be performed without discontinuing anticoagulation, especially when ultrasound guidance is used (2). However, deep blocks should be approached with caution and often follow the same timing and discontinuation guidelines as neuraxial procedures.

Different anticoagulants carry distinct bleeding risks and management timelines. Warfarin, a vitamin K antagonist, should generally be discontinued four to five days before deep blocks (2). LMWH should be withheld for at least 12 hours after prophylactic doses and 24 hours after therapeutic doses. Direct oral anticoagulants (DOACs), such as rivaroxaban, apixaban, and dabigatran, are typically withheld for 24–48 hours before deep blocks, depending on renal function and the agent’s pharmacokinetics, given their shorter half-lives.

Some evidence suggests that both superficial and deep peripheral nerve blocks can be safely performed in select patients undergoing anti-coagulant therapy. Taormina et al. (2015) found no increase in major bleeding when superficial and deep blocks were combined in a study of patients on rivaroxaban after joint arthroplasty (3). These findings suggest that, with meticulous ultrasound guidance and precise anatomical technique, the risk of bleeding can be minimized, even during ongoing anticoagulation. However, given the limited prospective data, this evidence should be cautiously interpreted and applied within a framework of individualized risk assessment and guideline adherence.

References

1. Poredoš P. Peripheral nerve blocks in patients on antithrombotic drugs – a rescue or an unnecessary risk? Acta Clin Croat. 2022;61(Suppl 2):67-77. doi:10.20471/acc.2022.61.s2.08
2. 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 October 17, 2025. doi:10.1136/rapm-2024-105766
3. Chelly JE, Metais B, Schilling D, Luke C, Taormina D. Combination of Superficial and Deep Blocks with Rivaroxaban. Pain Med. 2015;16(10):2024-2030. doi:10.1111/pme.12801