Safety and Efficacy Study of TNX-102 SL in Participants With PTSD

Inclusion Criteria:

1. Male or female between 18 and 75 years of age, at the time of signing ICF, inclusive.
2. Diagnosed with current (past month) PTSD as determined by the MINI 7.0.2 Module H (PTSD).
3. Index trauma(s) resulting in PTSD must meet DSM-5 Criterion A for PTSD as described in the CAPS 5, must have occurred within 9 years of Screening Visit 1, and must have occurred when the participant was ≥18 years of age.
4. Willing and able to withdraw and refrain from opioids for the course of the study.
5. Willing to refrain from use of all other formulations of cyclobenzaprine for the course of the study.
6. Willing and able to refrain from antidepressants and other excluded medications.
7. Capable of reading and understanding English and able to provide written informed consent to participate.
8. Willing to comply with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol.
9. If female, either not of childbearing potential or practicing a medically acceptable method of birth control throughout the study.
10. Body mass index (BMI) within the range 17.5 - 35 kg/m^2 (inclusive).

Exclusion Criteria:

1. Current or ongoing exposure to the trauma that resulted in the PTSD (ie, non-work-related trauma such as ongoing domestic abuse).
2. Increased risk of suicide, based on the investigator's judgment that is of a severity that is not appropriate for outpatient management, or that warrants additional therapy excluded by the protocol.
3. Significant (eg, moderate or severe) comorbid traumatic brain injury (TBI) by history.
4. Severe depressive symptoms at screening or baseline.
5. Clinically significant laboratory abnormalities based on screening laboratory tests and/or medical history in the investigator's opinion.
6. Use of antidepressant medication within 2 months of baseline.
7. Female participants who are pregnant or lactating.
8. History of serotonin syndrome, severe allergic reaction or bronchospasm or known hypersensitivity to cyclobenzaprine or the excipients in TNX-102 SL or placebo formulations.
9. Seizure disorder.
10. Current moderate or severe sleep apnea not well controlled by positive airway pressure (PAP) or oral (mouthpiece) devices.
11. Has received any other investigational drug within 90 days before Screening or has taken cyclobenzaprine within 21 days of the Randomization visit.
12. Previous participation in any other study with TNX-102 SL.
13. Family member of investigative staff.