- Subjects who cannot or will not agree to stop local regional pain treatments during the study (nerve/plexus blocks or ablation, neurosurgical procedures for pain control, botulinum toxin injections for control of chronic low back pain, steroid injections in the lower back or inhalation analgesia). The subject must not have had a nerve/plexus block within 4 weeks of the screening visit, neuroablation within 6 months of the screening visit, a botulinum toxin injection in the low back region within 3 months of the screening visit, steroid injections in the lower back within 6 weeks of the screening visit, or intravenous or intramuscular steroid injections within 4 weeks of the screening visit;