Veterans' chronic back pain may be eased by natural brain molecules in new trial

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Veterans with chronic low back pain * Based on medical history and medical records, have low back pain (Thoracic Vertebrae 6 or below) present on most days for the preceding 6 months or longer, and fulfill all disease diagnostic criteria (please see disease diagnostic criteria below) * Have a weekly mean of 24-hour average pain score 4 at baseline * Negative pregnancy test if female. Sexually active subjects are required to use a medically acceptable form of birth control if they are of childbearing potential and could become pregnant during the study. A medically acceptable form of birth control includes non-hormonal intrauterine devices, surgical sterilization, or double barrier methods (e.g. diaphragm with contraceptive jelly, condom with contraceptive foam, cervical caps with contraceptive jelly). Sexual abstinence with agreement to continue abstinence or to use a medically acceptable method of contraception (as listed above) should sexual activity occur is permissible * No change in medications less than 4 weeks before baseline * No anticipated need to alter psychotropic or pain medications for the 6-wk study duration (as determined by study physician's review of records and/or discussion with prescribing physician) * Ability to fully participate in the informed consent process Exclusion Criteria: * Unstable medical or neurological illness, including seizures, renal impairment or cerebral vascular accident (CVA) * Use of oral contraceptives or other hormonal supplements-this is out of caution, as it is unknown if the study medications would impact the efficacy of hormonal contraception * Significant suicidal or homicidal ideation that necessitates intervention * Daily use of long or short-acting narcotic medications (PRN use will be considered) * Current DSM-5 diagnosis of bipolar disorder, schizophrenia, or other psychotic disorder, or cognitive disorder due to a general medical condition * Female participants who are pregnant or breast-feeding * Known allergy to study medication * History of moderate or severe TBI (mild TBI is permissible) * DSM-5 criteria met for alcohol and/or other substance abuse or dependence within past three months (excludes caffeine and nicotine) * Have received epidural steroids, facet block, nerve block or other invasive procedures aimed to reduce low back pain within the past 3 months prior to Visit 1 * Have ongoing or anticipated disability compensation or litigation issues, in the best judgment of the investigator * Have a presence of any factors/conditions, medical or other, that in the judgment of the investigator may interfere with performance of study outcome measures, such as treatment-refractory history * Have serious or unstable cardiovascular, hepatic, renal, metabolic, respiratory, or hematologic illness, symptomatic peripheral vascular disease, or other medical condition or psychiatric conditions that, in the opinion of investigator and study physician, would compromise participation or be likely to lead to hospitalization during the study