Patients with upper motor neuron disease, such as multiple sclerosis, can present with severe spasticity in the perioperative period. In most cases, this can be managed with a combination of preoperative oral medications, regional or neuraxial anesthetic techniques, and intravenous muscle relaxants. We describe the clinical presentation of a patient with multiple sclerosis and the successful use of intravenous dantrolene sodium postoperatively for the treatment of exacerbated spasticity refractory to traditional management.