Methoxyflurane for IUD Insertion and Endometrial Biopsy

NCT07046572 | Recruiting

• 1 other identifier: REB 25-0041-A
• Study Type: interventional
• Target: 174
• Locations: 1 country
• Sites: 1

Brief Summary

The aim of this study is to determine if 3ml of inhaled Methoxyflurane, in the form of a Penthrox inhaler, reduces pain during IUD insertion and/or endometrial biopsy. The proposed study is a double-blind, placebo-controlled RCT. Each participant will be randomly assigned to one of two arms:

1. 1.Intervention (3ml of Methoxyflurane via a Penthrox inhaler)
2. 2.Placebo (3ml of normal saline via an identical placebo Penthrox inhaler)

Conditions

Endometrial Biopsy; Intrauterine Devices

Keywords

methoxyflurane

Outcome Measures

Primary Outcomes (1)

• Global pain score

  Patient reported pain by the 100 mm Visual Analogue Scale (VAS), minimum value 0 (no pain at all) and maximum value 100 (worst pain imaginable), higher scores indicate greater pain intensity.

  5-minutes following the completion of the procedure

Secondary Outcomes (6)

• Pain scores during procedure

  During the procedure

• Immediate complications and side effects

  Immediately after the completion of the procedure

• Difficulty for provider to complete the procedure

  Immediately after the completion of the procedure

• Length of time for procedure completion

  During the procedure

• Patient satisfaction

  Immediately after the completion of the procedure

Study Arms (2)

3ml of Methoxyflurane

EXPERIMENTAL

3ml of Methoxyflurane via a Penthrox inhaler

Drug: Methoxyflurane - Penthrox

3ml of normal saline

PLACEBO COMPARATOR

3ml of normal saline via an identical placebo Penthrox inhaler

Other: Placebo Penthrox inhaler

Interventions

Methoxyflurane - Penthrox DRUG

3ml of Methoxyflurane via a Penthrox inhaler

3ml of Methoxyflurane

Placebo Penthrox inhaler OTHER

3ml of normal saline via an identical placebo Penthrox inhaler

3ml of normal saline

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Any participant ≥18 years and ≤ 65 years presenting for an IUD insertion or endometrial biopsy
• For IUD insertion, only nulliparous patients
• English speaking participants only
• Availability of a ride home from the appointment

You may not qualify if:

• Use of pain medication that is not an NSAID or acetaminophen (e.g. opioids, benzodiazepines) within past 24 hours
• Misoprostol administration within 24 hours
• Breastfeeding
• Any diagnosed chronic pain syndromes (e.g. fibromyalgia, vaginismus)
• Allergy to methoxyflurane
• Renal or liver disease
• Known or genetically susceptible to malignant hyperthermia or a history of severe adverse reactions in either patient or relatives
• Baseline vital signs of systolic blood pressure \<100, diastolic blood pressure \<60 and/or pulse \<60.
• Previous unsuccessful office attempt of IUD insertion or endometrial biopsy by the same practitioner (note of clarification: previous unsuccessful IUD insertion or biopsy attempt by a different practitioner will still be eligible)
• Clinically evident respiratory impairment

Sponsors & Collaborators

• Mount Sinai Hospital, Canada: lead
• Matthew Morton Research Award: collaborator

Study Sites (1)

OPG

Toronto, Ontario, M5G 1Z5, Canada

RECRUITING

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Masking Details: The research coordinator (who is not involved in direct patient care) will open the allocation envelopes without the presence of the participant or the provider. They will prepare the Penthrox inhalers with either 3 mL methoxyflurane or 3 mL normal saline with a few drops of methoxyflurane on the outside of the inhaler to maintain blinding (as methoxyflurane has a distinct smell). The research coordinator will label each Penthrox inhaler with the study ID number. The provider (who is blinded to the study) will enter the patient room with the procedure tray and the Penthrox inhaler. They will instruct the patient to inhale for 10 breaths with their finger covering the dilutor hole of the Penthrox inhaler. Once the patient has taken 10 breaths, the research assistant will start a timer for 5 minutes. The research assistant will inform the OB-GYN once the 5 minutes have passed and at that point the OB-GYN will start the procedure. All data will remain blinded until data analysis.
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator (Dr.)

Model Details: The proposed study is a double-blind randomized controlled trial. Participants will be recruited from Mount Sinai Hospital outpatient gynecology clinics. Recruitment, consent, randomization, procedure, and post-procedure survey will occur during the same visit. Each participant will be randomly assigned to one of two arms: 1) intervention (3ml of Methoxyflurane via a Penthrox inhaler) or 2) placebo (3ml of normal saline via an identical placebo Penthrox inhaler). The primary outcome will be a global pain score, which will be patient-reported by the 100 mm Visual Analogue Scale (VAS) following the procedure.

Study Record Dates

• First Submitted: June 20, 2025
• First Posted: July 1, 2025
• Study Start: July 24, 2025
• Primary Completion: December 1, 2025
• Study Completion: March 1, 2026
• Last Updated: July 30, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)