Safety and Preliminary Effectiveness of AV650 in Patients With Spasticity Due to Spinal Cord Injury

Inclusion Criteria: * Subjects who provide written informed consent. * Male or female subjects aged 18 to 70 years. * In the judgment of the Principal Investigator, able to comply with protocol requirements. * Subjects willing and able to withdraw from other anti-spasmodic/muscle relaxant drugs for at least two weeks before randomization (including but not limited to baclofen, benzodiazepines, clonazepam, clonidine, dantrolene, diazepam, gabapentin, and tizanidine). * Neurological level between C-4 and T-12 spinal cord levels. * SCI duration of 6 or more months. * Muscle tone sufficient to score at least two (2) on the Ashworth Scale for at least one of the following lower muscle groups: ankle plantar flexors (gastrocnemius), knee extensors (quadriceps), knee flexors (hamstrings) and/or hip adductors (adductors) and seven (7) for the most spastic limb. * ASIA Impairment Scale Exam score of B, C or D. * Female subjects of childbearing potential must be either surgically sterile or using an effective method of contraception. * Female subjects of childbearing potential must have a negative urine pregnancy test at baseline (Study Day 0). Exclusion Criteria: * Subjects with a known hypersensitivity to lidocaine or non-steroidal analgesics. * Subjects with clinically significant cardiovascular, pulmonary, endocrine, hepatic, renal, neurological, metabolic, or psychiatric disease. * Any recent history of mental illness, drug addiction, recreational drug use, or alcoholism and/or any similar condition that the investigator feels should prohibit study participation. * Any significant illness during the four weeks preceding Study Day 1. * History of cancer or inflammatory arthritis of large joints. * History of gastric or duodenal ulcer. * Concurrent symptomatic urinary tract infections with fever. * Severe physical injury, direct impact trauma, or neurological trauma within the last 6 months not including Spinal Cord Injury. * ASIA Impairment Scale score of A or E. * Uncontrolled hypertension or hypotension. * Percussive tenderness of vertebral body or spinous process. * Subjects with corrective surgery to or contracture of the measurable hip, knee, or ankle joints. * Subjects known to be Hepatitis B or HIV positive. * Female subjects who are pregnant or nursing. * Subjects who have received an investigational drug within 30 days before Screening visit. * Subjects with any documented episodes of seizures. * Subjects requiring use of clinically relevant 2C19 or 2D6 inhibitors, or concomitant use of lidocaine. * Use of rescue medication(s) within 48 hours of baseline procedures.