Recruiting

Methoxyflurane

Sponsor:

Mount Sinai Hospital, Canada

Code:

NCT07046572

Conditions

Endometrial Biopsy

Intrauterine Devices

Eligibility Criteria

Sex: Female

Age: 18 - 65

Healthy Volunteers: Accepted

Interventions

Methoxyflurane - Penthrox

Placebo Penthrox inhaler

Study Details

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. 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).

Conditions

Endometrial Biopsy

Intrauterine Devices

Study ID

NCT07046572

Start date

Jul 24, 2025

Status verified date

Jul, 2025

Completion date

Mar 1, 2026

Anticipated

Primary completion date

Dec 1, 2025

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Female

Age: 18 - 65

Healthy Volunteers: Accepted

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

Study Design

Enrollment

174 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Other

Interventions and Outcome Measures

Arms

experimental: 3ml of Methoxyflurane

3ml of Methoxyflurane via a Penthrox inhaler

placebo comparator: 3ml of normal saline

3ml of normal saline via an identical placebo Penthrox inhaler

Interventions

Methoxyflurane - Penthrox

3ml of Methoxyflurane via a Penthrox inhaler

Placebo Penthrox inhaler

3ml of normal saline via an identical placebo Penthrox inhaler

Primary outcome measure

  • Global pain score [ Time Frame: 5-minutes following the completion of the procedure ]

Central Contacts and Locations

Locations

OPG

Recruiting

Toronto, Ontario, Canada, M5G 1Z5

Contacts

Dr. Mara Sobel, MD

416-586-8273Mara.Sobel@sinaihealth.ca

Principal Investigator:

Dr. Mara Sobel, MD

More Information

Sponsor

Mount Sinai Hospital, Canada

Last update posted

Jul 30, 2025

Last verified

Jul, 2025

Keywords

  • methoxyflurane

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Mount Sinai Hospital, Canada on 2025-07-30.