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Study of nitrous oxide and medical air inhalation in elderly patients with treatment-resistant depression

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on Resistant Depression in elderly individuals. The research examines the effects of two medical gases: KALINOX (a mixture of nitrous oxide and oxygen) compared to Medical Air. Resistant depression occurs when standard antidepressant treatments do not provide sufficient relief from depressive symptoms.

The purpose of this study is to evaluate how depressive symptoms change when patients receive either KALINOX or medical air through inhalation. The treatment involves breathing the assigned medical gas through a face mask for up to 60 minutes. The study will monitor changes in depression symptoms at various times after treatment - specifically at 2 hours, 24 hours, and then at one and two weeks after receiving the gas.

During the study, participants will undergo various assessments including MRI scans to examine brain structure and function. The research will also use specialized scales to measure depression severity and monitor any potential side effects. The study uses a method where neither the patient nor the doctor knows which gas is being administered to ensure unbiased results.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Your depression severity will be measured using the MADRS scale (a standardized depression rating scale).

    Various medical evaluations will be performed, including brain imaging with ultrasound and MRI scans.

  2. Step 2

    Treatment administration

    You will receive either KALINOX (a mixture of 50% nitrous oxide and 50% oxygen) or medical air through a face mask.

    The type of gas you receive will be randomly assigned, and neither you nor the medical staff will know which treatment you are receiving.

  3. Step 3

    Follow-up assessments

    Your depression symptoms will be evaluated at specific intervals: 2 hours, 24 hours, 1 week, and 2 weeks after treatment.

    Additional assessments will include:

    Depression symptom evaluation using multiple rating scales

    Monitoring for potential side effects

    Brain imaging to assess changes in brain function and structure

  4. Step 4

    Final evaluation

    A comprehensive assessment will be conducted at the end of the 2-week period.

    The evaluation will include depression scales, safety assessments, and brain imaging studies to measure the treatment's effects.

Who can join the trial?

8 criteria

  • Age between 60 and 90 years old
  • Have a diagnosed depressive episode according to DSM-5 criteria (a standard guide used by mental health professionals to diagnose mental conditions), confirmed by a special diagnostic interview
  • Score higher than 20 points on the MADRS scale (a test that measures depression severity)
  • Have not responded well to at least one properly administered antidepressant treatment for the current depressive episode
  • Be physically able to use a facial mask for treatment delivery
  • Be willing and able to provide written informed consent to participate in the study
  • Have active health insurance or similar coverage
  • Both men and women can participate

Who cannot join the trial?

15 criteria

  • Age below 65 years or above 85 years
  • Current diagnosis of bipolar disorder (a mental health condition with alternating periods of depression and elevated mood)
  • History of psychotic symptoms (loss of contact with reality, such as hallucinations or delusions)
  • Presence of cognitive impairment (significant problems with memory or thinking)
  • Current substance abuse or dependence
  • Serious medical conditions that are not well-controlled
  • Previous adverse reactions to nitrous oxide or similar gases
  • Current use of medications that could interact with the study treatment
  • Inability to provide informed consent
  • Participation in another clinical trial within the past 30 days
  • Pregnancy or breastfeeding
  • History of vitamin B12 deficiency (low levels of vitamin B12 in the blood)
  • Severe respiratory problems
  • Untreated high blood pressure
  • Recent major surgery within the past 3 months
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Investigated drugs

  • Nitrous oxide/oxygen mixture (MEOPA)

    This is a medical gas mixture containing nitrous oxide and oxygen. It's used as an inhaled treatment for treatment-resistant depression. The gas mixture has mild anesthetic and pain-relieving properties and may help improve depression symptoms when other treatments haven't worked well enough.

  • Medical air

    This is purified room air used as a comparison treatment (control) in the study. Medical air is clean, filtered air that contains the same proportions of oxygen and nitrogen as regular room air. It's used to help determine if the nitrous oxide mixture is more effective than breathing normal air.

  • Antidepressants

    These are medications already being taken by the study participants to treat depression. The study looks at whether adding nitrous oxide treatment can help improve depression symptoms in elderly patients who haven't responded well enough to antidepressants alone.

What is already known about the treatment

  • Nitrous Oxide (MEOPA)

    A medical gas mixture administered through inhalation, typically containing 50% nitrous oxide and 50% oxygen, used in clinical settings for treatment-resistant depression in elderly patients. This fast-acting substance has been extensively studied in medical literature and shows promising results in managing depressive symptoms, particularly in cases where traditional antidepressants have proven ineffective. The medication works by modulating the NMDA receptor system in the brain, influencing neurotransmitter activity and potentially providing rapid antidepressant effects. As an inhalational anesthetic and analgesic agent, it's classified under the pharmacological category of dissociative agents and is administered under controlled medical supervision.

  • Medical Air

    A pharmaceutical-grade gas mixture used as a control substance in clinical trials, consisting of the same composition as atmospheric air but purified and standardized for medical use. It serves as an important comparator in respiratory and psychiatric studies, particularly when evaluating the effectiveness of other gas-based treatments. Medical air is administered through the same delivery systems as other medical gases and is classified as a medical device or pharmaceutical product depending on its specific use and regulatory context.

Investigated diseases

Treatment-Resistant Depression in the Elderly - A severe form of depression that occurs in older adults and does not respond adequately to standard antidepressant treatments. The condition is characterized by persistent feelings of sadness, loss of interest in activities, changes in sleep patterns, and decreased energy levels that continue despite trying multiple treatment approaches. Elderly patients may experience additional symptoms such as memory problems, physical health complaints, and social withdrawal. The condition often develops gradually and can be complicated by other age-related health issues.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-517549-15-00Protocol codePROTO-BRAINEstimated enrolment60 patientsSponsorCentre Hospitalier Regional Universitaire De Tours

sourced from the EU Clinical Trials Register and site verification

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