Pharmacotherapy with amantadine and mexiletine was effective for phantom limb pain that developed after lower-limb amputation surgery

Abstract

A 59-year-old Japanese woman suffered from necrotizing fasciitis in her right lower limb and underwent amputation of the limb at the hip joint. Immediately after the surgery, she experienced phantom sensations in the right lower limb, dysesthesia, and stump pain. We started pregabalin treatment (oral 150 mg/day) on postoperative day 3, but the phantom limb sensation and dysesthesia did not improve. When amantadine (oral 200 mg/day) was started on postoperative day 8, her symptoms gradually improved. Mexiletine (oral 200 mg/day) was started on postoperative day 31, and symptoms further alleviated. In the combination therapy with pregabalin (oral 450 mg/day), amantadine (oral 450 mg/day), and mexiletine (oral 300 mg/day) to treat phantom limb pain, amantadine was particularly effective. The patient's positive outcome suggests that amantadine is an effective treatment option for phantom limb pain and phantom limb sensations after limb amputation.