← Back to Clinical Trials
Recruiting Phase 4 NCT03642028

NCT03642028 Suvorexant: A Dual Orexin Receptor Antagonist for Treating Sleep Disturbance in Posttraumatic Stress

◆ AI Clinical Summary
Plain-language summary for patients
Clinical Trial Summary
NCT ID NCT03642028
Status Recruiting
Phase Phase 4
Sponsor VA Office of Research and Development
Condition Sleep Initiation and Maintenance Disorders
Study Type INTERVENTIONAL
Enrollment 190 participants
Start Date 2019-08-30
Primary Completion 2025-12-31

Eligibility & Interventions

Sex All sexes
Min Age 18 Years
Max Age 75 Years
Study Type INTERVENTIONAL
Interventions
SuvorexantPlacebo

Eligibility Fast-Check

Enter your details for a quick preliminary check. This does not replace medical advice.

What to Expect as a Participant

You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.

Phase 4 studies follow an already-approved treatment in real-world conditions to monitor long-term safety and effectiveness.

This trial targets 190 participants in total. It began in 2019-08-30 with a primary completion date of 2025-12-31.

⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.

Brief Summary

Post-traumatic stress disorder (PTSD) is a common consequence of combat that can result in trauma-related hyperarousal and sleep disturbances. Poor sleep, one of the most common complaints in Veterans with PTSD, can be distressing, impair concentration and memory, and contribute to physical health conditions, such as metabolic syndrome, inflammation, and cardiovascular disease. The orexin neuropeptide system underlies both sleep and stress reactivity. Suvorexant, a drug that reduces orexin, improves sleep in civilians, but has not yet been tested in Veterans with PTSD. This study will test whether suvorexant can improve sleep disturbances and PTSD symptoms in Veterans. Suvorexant may benefit Veterans by improving sleep quickly while also reducing PTSD symptoms over the long term, and with fewer side effects that were common in previous medications used to treat these conditions. Improving Veterans' sleep and PTSD symptoms could lead to better emotional and physical well-being, quality of life, relationships, and functioning.

Eligibility Criteria

Inclusion Criteria: * Men and Women, age range of 18 to 75, with a history of US military service, capable of reading and understanding English, and able to provide written informed consent * Criterion A event meets DSM-5 criteria * PTSD symptoms \>3 months duration as indexed by a CAPS-5 12 and a partial PTSD diagnosis at screening * Insomnia indicated by an ISI score \> 14 * Subjects on non-exclusionary medications must be on a stable dose for at least 4 weeks prior to randomization, which includes the Selective Serotonin Reuptake Inhibitors (SSRIs) e.g.: * Sertraline * Paroxetine * Fluoxetine * Fluvoxamine * Citalopram * Escitalopram * Serotonin-norepinephrine reuptake inhibitors (SNRIs), e.g.: * Desvenlafaxine * Duloxetine * Levomilnacipran * Venlafaxine * For subjects who are in psychotherapy, treatment must be stable for 6 weeks * Women of child-bearing potential must not be pregnant or have plans for pregnancy or breastfeeding during the study and must use a medically acceptable method of birth control, e.g.: * oral * implantable * injectable * transdermal contraceptive * intrauterine device * double-barrier method * Sleep apnea score \<30; if screening indicates mild or moderate sleep apnea (score between 5 and 30), referral will be provided Exclusion Criteria: * DSM-5 alcohol, marijuana, and/or other drug use disorder in the last 3 months * Mild alcohol use not meeting criteria for moderate or severe use disorder may be allowed on a case-by-case basis * Mild or moderate marijuana use disorder may be allowed on a on a case-by-case basis * Manic or psychotic episode in the last 5 years * Exposure to trauma in the last 3 months * Prominent suicidal or homicidal ideation or any suicidal behavior in the past 3 months on the Columbia Suicide Severity Rating Scale (C-SSRS) or increased risk of suicide that necessitates additional therapy or inpatient treatment * Pre-existing severe sleep apnea (score \>30) in the absence of adherence to effective treatment (such as CPAP or oral device) or positive screen for severe sleep apnea by type III device (score \> 30) * Neurologic disorder or systemic illness affecting CNS function * Chronic or unstable medical illness including: * unstable angina * myocardial infarction within the past 6 months * congestive heart failure * preexisting hypotension or orthostatic hypotension * heart block or arrhythmia * chronic renal or hepatic failure * pancreatitis * severe chronic obstructive pulmonary disease * History of severe traumatic brain injury * Mild cognitive impairment assessed by the Montreal Cognitive Assessment * Pregnancy, breastfeeding and/or refusal to use effective birth control (for women) * Narcolepsy * Previous adverse reaction to a hypnotic * Current use of benzodiazepines, strong CYP3A inhibitors, or Digoxin Prohibited: * benzodiazepines * strong CYP3A inhibitors * Digoxin * Furthermore, CNS depressants (e.g., benzodiazepines, opioids, alcohol) increase the risk of CNS depression when co-administered with suvorexant and will not be allowed for safety reasons. * Since metabolism by CYP3A is the major elimination pathway for suvorexant, concomitant use of suvorexant with strong inhibitors of CYP3A (e.g., ketoconazole, itraconazole, posaconazole, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, boceprevir, telaprevir, telithromycin and conivaptan), moderate CYP3A inhibitors (e.g., amprenavir, aprepitant, atazanavir, ciprofloxacin, diltiazem, erythromycin, fluconazole, fosamprenavir, grapefruit juice, imatinib, verapamil), or strong CYP3A inducers (e.g., rifampin, carbamazepine and phenytoin) will not be allowed. * All concomitant medication use will be monitored and documented

Contact & Investigator

Central Contact

Sabra S Inslicht, PhD

✉ sabra.inslicht@va.gov

📞 (415) 221-4810

Principal Investigator

Sabra S Inslicht, PhD

PRINCIPAL INVESTIGATOR

San Francisco VA Medical Center, San Francisco, CA

Frequently Asked Questions

Who can join the NCT03642028 clinical trial?

This trial is open to participants of all sexes, aged 18 Years or older, up to 75 Years, studying Sleep Initiation and Maintenance Disorders. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.

What phase is the NCT03642028 trial and what does that mean for participants?

Phase 4 studies are conducted after a treatment has been approved. They monitor long-term safety and real-world effectiveness in a broader patient population.

Is NCT03642028 currently recruiting?

Yes, NCT03642028 is actively recruiting participants. Contact the research team at sabra.inslicht@va.gov for enrollment information.

Where is the NCT03642028 trial being conducted?

This trial is being conducted at Long Beach, United States, San Francisco, United States, Salisbury, United States, Charleston, United States.

Who is sponsoring the NCT03642028 clinical trial?

NCT03642028 is sponsored by VA Office of Research and Development. The principal investigator is Sabra S Inslicht, PhD at San Francisco VA Medical Center, San Francisco, CA. The trial plans to enroll 190 participants.

Related Trials

ClinicalMetric — Independent clinical trial intelligence platform. Not affiliated with NIH, ClinicalTrials.gov, the U.S. FDA, or any pharmaceutical company, hospital, or clinical research organization. Trial data is sourced from ClinicalTrials.gov for informational purposes only and does not constitute medical advice. Do not make any treatment, enrollment, or health decisions based solely on information found here — always consult a qualified healthcare professional. Full Disclaimer  ·  Last Reviewed: April 2026  ·  Data Methodology