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Recruiting Phase 2 NCT06636357

NCT06636357 Nitrous Oxide in the Treatment of Acute Suicidal Ideation

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Clinical Trial Summary
NCT ID NCT06636357
Status Recruiting
Phase Phase 2
Sponsor University of Zurich
Condition Suicidality
Study Type INTERVENTIONAL
Enrollment 85 participants
Start Date 2025-01-13
Primary Completion 2026-09-30

Eligibility & Interventions

Sex All sexes
Min Age 18 Years
Max Age 65 Years
Study Type INTERVENTIONAL
Interventions
50% N2O plus 50% O2Oxygen (O2)

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.

In Phase 2, researchers evaluate early signs of effectiveness. You may be randomized to receive the active treatment or a comparator. Monitoring continues closely.

This trial targets 85 participants in total. It began in 2025-01-13 with a primary completion date of 2026-09-30.

⚠ 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

The primary aim of the NITOS study is to investigate the potential rapid antisuicidal effects of N2O in the transdiagnostic treatment of suicidal ideation. On day 1, patients will receive either nitrous oxide (50% N2O balanced with oxygen) or placebo (50% oxygen balanced with air). Seven days after the first inhalation, a second inhalation will be performed. All patients will receive N2O at least once during this trial. While the first inhalation will be double-blind, only the patients but not the raters will be blinded to the second inhalation (day 8). For mechanism of action and prediction, a nested biomarker substudy will employ multimodal techniques including analysis of hair and blood samples, and EEG.

Eligibility Criteria

Inclusion criteria: * Ability to give written informed consent * Moderate to severe suicidal ideation defined as a score ≥3 on the Montgomery-Asberg Depression Rating Scale (MADRS; Schmidtke et al., 1985) suicide item (item #10) as well as a self-report Beck Scale for Suicide Ideation (BSS; Kliem et al., 2017) items #4 plus #5 score ≥ 2 * Plasma homocysteine level ≤ 14 µmol/l Exclusion criteria: * Organic, including symptomatic, mental disorders (F00-F09; lifetime diagnosis) * Schizophrenia, schizotypal and delusional disorders (F20-F29; lifetime diagnosis) * Mental and behavioral disorders due to psychoactive substance use. Nicotine and cannabis will be ignored (F10-F19) * Non-medical (i.e., recreational) use of inhalational N2O during the last 12 months * Past intolerance or hypersensitivity to N2O * Critical illness * Severe cardiac disease * Pregnancy or breastfeeding * Pulmonary hypertension * Chronic cobalamin or folate deficiency unless treated with folic acid and/or vitamin B12 * History or evidence of any other medical or neurological condition that would expose the subject to an undue risk of a significant adverse event as determined by the clinical judgment of the investigator * Treatment with ketamine/esketamine during the last 4 weeks * Treatment with opioid medications during the last 3 months * Treatment with vagus nerve stimulation (VNS) or electroconvulsive therapy (ECT) within the last 3 months * Recent (within the last 4 weeks) or current use of benzodiazepines in excess of 5 mg lorazepam or equivalent per day * Finally, any other factors that, in the investigator's judgment, would unduly impact patient safety or compliance during the study.

Contact & Investigator

Central Contact

Angelina Frasch

✉ angelina.frasch@pukzh.ch

📞 0041583843666

Frequently Asked Questions

Who can join the NCT06636357 clinical trial?

This trial is open to participants of all sexes, aged 18 Years or older, up to 65 Years, studying Suicidality. 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 NCT06636357 trial and what does that mean for participants?

Phase 2 trials evaluate whether the treatment shows signs of effectiveness while continuing to monitor safety. More participants are enrolled than in Phase 1 to help refine the treatment protocol.

Is NCT06636357 currently recruiting?

Yes, NCT06636357 is actively recruiting participants. Contact the research team at angelina.frasch@pukzh.ch for enrollment information.

Where is the NCT06636357 trial being conducted?

This trial is being conducted at Zurich, Switzerland.

Who is sponsoring the NCT06636357 clinical trial?

NCT06636357 is sponsored by University of Zurich. The trial plans to enroll 85 participants.

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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: July 2026  ·  Data Methodology