Pain ManagementPhase 3PAIN-THROXNCT07742007
Methoxyflurane Versus Usual Care for Non-Traumatic Pain in Emergency Departments
A Phase 3 study testing Analgesic management with Methoxyflurane as first-line treatment and Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center. in people with Pain Management, run by University Hospital, Tours at 3 sites in France.
Trial summary
Pain is one of the most frequent patient-reported symptoms in emergency departments (EDs). Pain management could be very challenging, notably for patients that must wait in an ED waiting room. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Pain Management
- What is being tested?
- Analgesic management with Methoxyflurane as first-line treatment and Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center.
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 164 participants
- Where
- 3 sitesFrance
- Study dates
- 16 Sep 2026to 16 Sep 2027
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adult ≥ 18 years
- Acute non-traumatic pain of moderate to severe intensity (VAS strictly greater than 39 mm)
- Able to independently assess their pain using a VAS and to record it independently on paper.
- Affiliated to a social security system
- Having signed informed consent
Who cannot join
- Age < 18 years
- Contraindications to methoxyflurane as stated in the Summary of Product Characteristics:
- Hypersensitivity to the active substance or to any other fluorinated anesthetic or to any excipient.
- Malignant hyperthermia: known malignant hyperthermia or genetic predisposition.
- History of serious adverse reactions (patient or relatives) after administration of inhaled anesthetics.
- History of signs of liver injury after use of methoxyflurane or halogenated hydrocarbons.
Show all 18Show fewer
- Clinically significant renal impairment
- Altered level of consciousness regardless of cause, including head trauma, drug or alcohol use
- Clinical evidence of cardiovascular instability
- Clinical evidence of respiratory depression
- Hemodynamically unstable patient (SBP < 100 mmHg, DBP < 30 mmHg)
- Patient having already received Methoxyflurane on the same day
- Patient having taken analgesic treatment prior to emergency consultation within 4 hours of admission.
- Pain ≤ 39 mm
- Pregnant, breastfeeding.
- Women of childbearing potential not using a highly effective method of contraception throughout the study. The absence of pregnancy must be confirmed by performing a pregnancy test. Patients who are unable to provide a urine sample at the time of inclusion will not be enrolled in the study.
- Subject under legal protection
- Patients currently within the exclusion period of another clinical trial.
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
France3 sites
CHU d'Angers
Angers, 49100
Aurélie FIENI, Dr
CHU d'Orléans
Orléans, 45100
Ayar VAITTINADA, Dr
CHRU Hôpitaux de Tours - Urgences de l'Hôpital Trousseau
Tours, CHRU de Tours, 37170
Mickael SOLETCHNIK, Dr., 0247471014, mickael.soletchnik@gmail.com
Mickael SOLETCHNIK, Dr
About this study
Official title: Methoxyflurane Versus Usual Care for Non-Traumatic Pain in Emergency Departments: the Multicenter, Open-label, Superiority PAIN-THROX Randomized Controlled Trial
Pain is one of the most frequent patient-reported symptoms in emergency departments (EDs). Pain management could be very challenging, notably for patients that must wait in an ED waiting room. In such context, antalgic drugs that could be used are mainly oral medications with the paracetamol (acetaminophen), the non-steroidal anti-inflammatory drugs and the weak and strong opioid drugs as the main available options, depending on the degree of pain. Those commonly used painkillers, with oral administration, need a delay (approximatively 20 to 30 minutes) before the full analgesic effect could be observed. Methoxyflurane is a self-administered inhaled analgesic used for over 40 years in countries such as Australia. Methoxyflurane has a rapid onset of action, is well tolerated and is widely used for moderate to severe traumatic pain, with several trials that have investigated it efficacy in such indication. However, no data are available concerning the management of non-traumatic painful diseases. Thus, the aim of the open-label, multicenter, and two parallel-arms superiority PAIN-THROX randomized controlled trial is to assess how using self-administered inhaled Methoxyflurane could reduce the time to pain relief comparatively with oral analgesic medications for patients seeking in an ED for non-traumatic painful diseases and who could wait in an ED waiting room.
Read the detailed description
Patients seeking in an ED for a non-traumatic painful disease and with a condition allowing staying in waiting room will be randomly allocated in a 1:1 ratio between Methoxyflurane (intervention group) or oral standard analgesic medications according to the degree of pain and based on the ED pain-management protocol.
Primary outcome will be the time to pain relief within the 30 minutes after randomization. Pain will be measured using the visual analogue scale. Secondary outcomes will be the time to pain relief within 3 subgroups according to the degree of pain at time to randomization (moderate, strong and intolerable), the evolution of the pain between 30 min and 2 hours post randomization, the need for rescue analgesic therapies and the occurrence adverse events.
- Conditions
- Pain Management
- Being tested
- Analgesic management with Methoxyflurane as first-line treatment, Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center.
- Keywords
- Non-traumatic pain, methoxyflurane, Emergency department, analgesic management
- Medical subject headings
- Agnosia, Emergencies
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Analgesic management with Methoxyflurane as first-line treatmentDrug
The investigational medicinal product is methoxyflurane, presented as a liquid for vapor inhalation, supplied in 3 mL vials and marketed under the name Penthrox®. Each vial contains 3 mL of methoxyflurane at 99.9%, and includes butylated hydroxytoluene (E321) as an excipient with known effect (0.01% w/w).
Each pack contains one methoxyflurane vial, an inhaler, and an activated carbon chamber.
Methoxyflurane is self-administered under the supervision of a trained healthcare professional, either a physician or a nurse. Administration is performed using the provided handheld inhaler.
Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center.Drug
Administration of oral analgesic treatment in the emergency reception area according to the protocol in force in the emergency department.
| Study group | Role | What they receive |
|---|---|---|
| Experimental Group | Experimental | analgesic management with Methoxyflurane as first-line treatment Receives: Drug: Analgesic management with Methoxyflurane as first-line treatment |
| Control group | Other | Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center. Receives: Drug: Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time to Pain Reduction of at Least 30 mm on the Visual Analog Scale (VAS)
Time from randomization to the first decrease of at least 30 mm from baseline pain score measured on a 100-mm Visual Analog Scale (VAS), assessed within the 30 minutes after randomization.
The VAS is a simple pain measurement tool consisting of placing a mark on a colored ruler graduated in millimeters, thereby associating a numerical value ranging from 0 (no pain) to 100 millimeters (unbearable pain).
Measured: At Inclusion An at 3, 5, 10, 15, 20, 25, and 30-minutes post randomisation
Secondary outcomes (5)
Evaluate the effect of methoxyflurane based on pain intensity
Assess the effect of methoxyflurane in each of the three subgroups defined by pain intensity and categorized as "moderate" pain (VAS between 40 and 59), "severe" pain (VAS between 60 and 79 mm), and "unbearable" pain (VAS ≥ 80 mm) at enrollment
Measured: from baseline to 30 minutes after randomization
Compare the prolonged analgesic effect (ranging from 30 minutes to 2 hours) of methoxyflurane
Compare the prolonged analgesic effect of methoxyflurane with that of "standard"pain management with the measurement of Pain Intensity (VAS) at 60, 90, and 120 Minutes Post-Randomization
Measured: At 60 minutes after randomization, 90 minutes and 120 minutes
Use of Rescue Analgesic Treatment After 30 Minutes Post-Randomization
Participants requiring any analgesic treatment due to insufficient pain relief or recurrence of pain more than 30 minutes after randomization.
Measured: More than 30 minutes after randomization
Class of Rescue Analgesic Treatment Used After 30 Minutes Post-Randomization
Therapeutic class of the analgesic treatment administered for insufficient pain relief or recurrence of pain more than 30 minutes after randomization.
Measured: More than 30 minutes after randomization
Adverse Events and Serious Adverse Events
Number of participants experiencing adverse events (AEs) and serious adverse events (SAEs) during the study period.
Measured: From baseline to 24 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Aug 2026
- Study start16 Sep 2026 (estimated)
- Primary completion15 Sep 2027 (estimated)
- Study completion16 Sep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pain ManagementStudies of the same condition, open and under way.
- More trials run by University Hospital, ToursThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 164 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Tours
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07742007
- Sponsor's protocol ID
- DR250268 - PAIN-THROX
- Other IDs
- 2025-525001-21-00, 2025
- Acronym
- PAIN-THROX
- Status last verified
- Jul 2026
- First submitted
- 16 Jul 2026
- Last updated
- 3 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Methoxyflurane Versus Usual Care for Non-Traumatic Pain in Emergency Departments: the Multicenter, Open-label, Superiority PAIN-THROX Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07742007
- Acronym / sponsor ID
- PAIN-THROX / DR250268 - PAIN-THROX
- Conditions
- Pain Management
- Keywords
- Non-traumatic pain, methoxyflurane, Emergency department, analgesic management
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 164 participants (estimated)
- Lead sponsor
- University Hospital, ToursUniversity, hospital or other
- Study start
- 16 Sep 2026 (estimated)
- Primary completion
- 15 Sep 2027 (estimated)
- Study completion
- 16 Sep 2027 (estimated)
- First posted
- 3 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Pain is one of the most frequent patient-reported symptoms in emergency departments (EDs). Pain management could be very challenging, notably for patients that must wait in an ED waiting room. In such context, antalgic drugs that could be used are mainly oral medications with the paracetamol (acetaminophen), the non-steroidal anti-inflammatory drugs and the weak and strong opioid drugs as the main available options, depending on the degree of pain. Those commonly used painkillers, with oral administration, need a delay (approximatively 20 to 30 minutes) before the full analgesic effect could be observed. Methoxyflurane is a self-administered inhaled analgesic used for over 40 years in countries such as Australia. Methoxyflurane has a rapid onset of action, is well tolerated and is widely used for moderate to severe traumatic pain, with several trials that have investigated it efficacy in such indication. However, no data are available concerning the management of non-traumatic painful diseases. Thus, the aim of the open-label, multicenter, and two parallel-arms superiority PAIN-THROX randomized controlled trial is to assess how using self-administered inhaled Methoxyflurane could reduce the time to pain relief comparatively with oral analgesic medications for patients seeking in an ED for non-traumatic painful diseases and who could wait in an ED waiting room.
Detailed description
Patients seeking in an ED for a non-traumatic painful disease and with a condition allowing staying in waiting room will be randomly allocated in a 1:1 ratio between Methoxyflurane (intervention group) or oral standard analgesic medications according to the degree of pain and based on the ED pain-management protocol.
Primary outcome will be the time to pain relief within the 30 minutes after randomization. Pain will be measured using the visual analogue scale. Secondary outcomes will be the time to pain relief within 3 subgroups according to the degree of pain at time to randomization (moderate, strong and intolerable), the evolution of the pain between 30 min and 2 hours post randomization, the need for rescue analgesic therapies and the occurrence adverse events.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Experimental Group | Experimental | Drug: Analgesic management with Methoxyflurane as first-line treatmentanalgesic management with Methoxyflurane as first-line treatment |
| Control group | Other | Drug: Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center.Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Adult ≥ 18 years
- Acute non-traumatic pain of moderate to severe intensity (VAS strictly greater than 39 mm)
- Able to independently assess their pain using a VAS and to record it independently on paper.
- Affiliated to a social security system
- Having signed informed consent
Key exclusion criteria (18 listed)
- Age < 18 years
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Analgesic management with Methoxyflurane as first-line treatmentThe investigational medicinal product is methoxyflurane, presented as a liquid for vapor inhalation, supplied in 3 mL vials and marketed under the name Penthrox®. Each vial contains 3 mL of methoxyflurane at 99.9%, and includes butylated hydroxytoluene (E321) as an excipient with known effect (0.01% w/w). Each pack contains one methoxyflurane vial, an inhaler, and an activated carbon chamber. Methoxyflurane is self-administered under the supervision of a trained healthcare professional, either a physician or a nurse. Administration is performed using the provided handheld inhaler. | Drug | Experimental Group |
| Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center.Administration of oral analgesic treatment in the emergency reception area according to the protocol in force in the emergency department. | Drug | Control group |
Primary outcome
Time to Pain Reduction of at Least 30 mm on the Visual Analog Scale (VAS)
Time frame: At Inclusion An at 3, 5, 10, 15, 20, 25, and 30-minutes post randomisation
Time from randomization to the first decrease of at least 30 mm from baseline pain score measured on a 100-mm Visual Analog Scale (VAS), assessed within the 30 minutes after randomization. The VAS is a simple pain measurement tool consisting of placing a mark on a colored ruler graduated in millimeters, thereby associating a numerical value ranging from 0 (no pain) to 100 millimeters (unbearable pain).
5 secondary outcomes
Evaluate the effect of methoxyflurane based on pain intensity
Time frame: from baseline to 30 minutes after randomization
Compare the prolonged analgesic effect (ranging from 30 minutes to 2 hours) of methoxyflurane
Time frame: At 60 minutes after randomization, 90 minutes and 120 minutes
Use of Rescue Analgesic Treatment After 30 Minutes Post-Randomization
Time frame: More than 30 minutes after randomization
Class of Rescue Analgesic Treatment Used After 30 Minutes Post-Randomization
Time frame: More than 30 minutes after randomization
Adverse Events and Serious Adverse Events
Time frame: From baseline to 24 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Aug 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Analgesic management with Methoxyflurane as first-line treatment and Pain treatment according to the usual analgesic management protocol of the emergency department of the participating center. in people with Pain Management, run by University Hospital, Tours at 3 sites in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 18 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 3 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Mickael SOLETCHNIK, Dr. (0247471014, mickael.soletchnik@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time to Pain Reduction of at Least 30 mm on the Visual Analog Scale (VAS) (time frame: At Inclusion An at 3, 5, 10, 15, 20, 25, and 30-minutes post randomisation). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Aug 2026.