Skip to main content
OpenTrials
Recruiting

NCT Number: NCT07046572

Methoxyflurane for IUD Insertion and Endometrial Biopsy

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

The primary outcome is global pain score, which will be patient-reported by the 100 mm Visual Analogue Scale (VAS) 5-minutes following the procedure (endometrial biopsy or IUD insertion).

Recruiting

Interested in participating?

Request Info

Key information

Conditions

Endometrial Biopsy Intrauterine Devices

Age range

18 year–65 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

OPG

Toronto, Ontario, M5G 1Z5, Canada

Location status: Recruiting

Location contact

Dr. Mara Sobel, MD

CONTACT

[email protected]

416-586-8273

Dr. Mara Sobel, MD

PRINCIPAL_INVESTIGATOR

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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

Exclusion criteria

  • 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

Treatment and study plan

Methoxyflurane - Penthrox

Drug

3ml of Methoxyflurane via a Penthrox inhaler

Placebo Penthrox inhaler

Other

3ml of normal saline via an identical placebo Penthrox inhaler

Primary outcomes

  1. Global pain score

    Time frame: 5-minutes following the completion of the procedure

    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.

Secondary outcomes

  1. Pain scores during procedure

    Time frame: During the procedure

    Patient-reported verbal pain scores on a scale from 0 (no pain) to 10 (worst pain imaginable) at the following timepoints: baseline before inhaler, baseline after inhaler, insertion of speculum, tap cervix with sound, placement of tenaculum, sounding (IUD only), IUD insertion/endometrial biopsy, and 1-minute post-procedure. Higher scores indicate greater pain intensity.

  2. Immediate complications and side effects

    Time frame: Immediately after the completion of the procedure

    Provider-reported via written survey

  3. Difficulty for provider to complete the procedure

    Time frame: Immediately after the completion of the procedure

    Provider-reported on Likert scale, minimum 1 (least difficult) and maximum 5 (most difficult). Higher score indicates greater difficulty.

  4. Length of time for procedure completion

    Time frame: During the procedure

    Recorded via stopwatch

  5. Patient satisfaction

    Time frame: Immediately after the completion of the procedure

    Patient-reported via a written survey

  6. Patient Satisfaction

    Time frame: Immediately after the completion of the procedure

    Patient-reported via a 5-point Likert scale: very unsatisfied (1) to very satisfied (5). Higher score indicates greater dissatisfaction.

Sponsors and collaborators

Lead sponsor

Mount Sinai Hospital, Canada

Other

Collaborators

  • Matthew Morton Research Award

Registry information

Official study title

A Double-blind Placebo-controlled Randomized Controlled Trial (RCT) of 3ml Methoxyflurane for Intrauterine Device (IUD) Insertion and Endometrial Biopsy

Important dates

Study start
2025
Primary completion
2025
Study completion
2026
First posted
Jul 1, 2025
Registry last updated
Jul 30, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.