What are the labeled indications and injection technique for liposomal bupivacaine in dogs and cats?

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Liposomal bupivacaine (LB; Nocita, Elanco) carries two FDA-labeled indications: peri-incisional infiltration in dogs following cranial cruciate ligament surgery, and peripheral nerve block in cats undergoing onychectomy. All other uses — including soft tissue surgery, ovariohysterectomy, gastrointestinal surgery, and limb amputation — are off-label. 1358 The labeled dose and route differ by species and indication. The maximum labeled dose in dogs is 5.3 mg/kg bupivacaine base administered as a single peri-incisional subcutaneous infiltration at the time of surgical closure. 11 In cats, LB is labeled as a peripheral nerve block (not infiltration) for onychectomy. 15 The WSAVA guidelines confirm that the product provides up to 72 hours of postoperative analgesia following perineural administration in cats undergoing distal limb procedures and following infiltration in dogs undergoing cranial cruciate ligament surgery. 6 For peri-incisional infiltration in dogs, LB is injected into the subcutaneous tissues surrounding the incision at the time of closure. The liposomal vesicle structure releases bupivacaine slowly over time, with analgesia onset similar to standard bupivacaine and duration up to 72 hours. 12 Because LB does not diffuse appreciably through tissue planes, incomplete blockade is a recognized limitation — in dogs undergoing enucleation treated with peri-incisional LB, 20% still required rescue analgesia, and most patients demonstrated only partial blockade on sensory threshold testing. 5 LB is therefore recommended as one component of a multimodal analgesic protocol rather than as a sole agent. 5 A critical contraindication applies to injection technique: LB must not be mixed with or injected concurrently at the same site as amide local anesthetics (lidocaine, bupivacaine HCl, mepivacaine, ropivacaine), as these agents disrupt the liposomal membrane and accelerate bupivacaine release, negating the extended-duration benefit. 2 Standard bupivacaine HCl is pha