Postoperative pain following major amputations represents a significant clinical challenge and is associated with increased morbidity, prolonged hospital stays, and a higher risk of chronic and phantom limb pain if not adequately managed. Multimodal analgesic strategies have demonstrated benefits in reducing pain intensity and opioid consumption, with intravenous (IV) lidocaine emerging as a therapeutic alternative due to its antihyperalgesic effects and modulation of central sensitization. We present the case of a 77-year-old male patient with a 20-year history of type 2 diabetes mellitus (T2DM) and a 15-year history of systemic arterial hypertension (SAH), non-smoker, with a history of alcohol consumption during youth (abstinent for the past 15 years), diagnosed with Texas stage III diabetic foot requiring supracondylar amputation of the left lower limb. Anesthetic management included spinal anesthesia with ropivacaine and fentanyl, placement of an epidural catheter without additional anesthetic use, and continuous IV lidocaine infusion at 1 mg/kg/h during the intraoperative period as part of a multimodal protocol. The patient remained hospitalized for 10 days and was discharged on postoperative day three. Pain control was effective, with a maximum visual analog scale (VAS) score of 4/10 in the post-anesthesia care unit and no significant need for rescue analgesia. During outpatient follow-up, no phantom limb pain or residual neuropathic pain was documented. IV lidocaine contributed to adequate analgesia, reduced opioid requirements, and favorable functional recovery. This case suggests that IV lidocaine infusion in the setting of major amputations may be an effective strategy within a multimodal analgesic approach, even in patients with significant comorbidities.