3 mL Inhaled Methoxyflurane for Intrauterine Device (IUD) Insertion

NCT07295054 | Recruiting Phase 4

• 1 other identifier: 2025-0056-B
• Study Type: interventional
• Target: 110
• Locations: 1 country
• Sites: 1

Brief Summary

Intrauterine device (IUD) insertion is a common contraceptive procedure often associated with moderate to severe pain, particularly among nulliparous individuals. Current pain management strategies, such as over-the-counter analgesics, are frequently inadequate. Methoxyflurane, a short-acting, self-administered inhaled analgesic, has been shown to provide rapid and effective pain relief in acute and procedural settings. This study aims to evaluate whether 3 mL of inhaled Methoxyflurane (via Penthrox inhaler) improves patient satisfaction by reducing pain and anxiety during IUD insertion.

Conditions

IUD

Keywords

Methoxyflurane; Penthrox

Outcome Measures

Primary Outcomes (1)

• Procedural pain intensity

  Patient-reported pain will be measured using the Numeric Rating Scale (NRS), a validated tool in which participants rate their pain intensity on a scale from 0 (no pain) to 10 (worst imaginable pain).

  20 minutes after post-procedure

Secondary Outcomes (9)

• Patient-centered measure of satisfaction with procedural sedation

  20 minutes after post procedure

• Patient satisfaction with pain management

  Baseline before procedure

• Patient distress

  Pre-procedure and post procedure 0,20 minutes and 24 hours.

• Patient Anxiety

  Pre-procedure and post procedure 0,20 minutes and 24 hours.

• Recall peak pain during procedure

  0 minutes after post procedure

Study Arms (2)

Intervention Group

EXPERIMENTAL

Participants will receive a Penthrox inhaler containing 3 mL of methoxyflurane. Before speculum insertion, they will take intermittent inhalations every 30-60 seconds (6-10 breaths), following monograph instructions. They may continue self-administering the inhaler as needed during the procedure. Participants will receive standard pain management prior to IUD insertion, which includes: 1) recommendation to use over-the-counter analgesics such as NSAIDs, and 2) the option to undergo a cervical block to minimize discomfort during the procedure.

Drug: Methoxyflurane

Placebo Group

PLACEBO COMPARATOR

Participants will receive an identical-looking inhaler containing 3 mL of normal saline. To maintain blinding, a drop of methoxyflurane will be placed on the outside of the device, which has no analgesic effect. Before speculum insertion, participants will take intermittent inhalations every 30-60 seconds (6-10 breaths), following monograph-style instructions, and may continue self-administering as needed during the procedure. Participants will receive standard pain management prior to IUD insertion, which includes: 1) recommendation to use over-the-counter analgesics such as NSAIDs, and 2) the option to undergo a cervical block to minimize discomfort during the procedure.

Drug: Saline

Interventions

Saline DRUG

3 mL of Normal Saline via an identical placebo handheld inhaler

Also known as: 0.9% sodium chloride

Placebo Group

Methoxyflurane DRUG

3 mL of Methoxyflurane via a handheld inhaler

Also known as: Penthrox

Intervention Group

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Patients with a uterus.
• Ages 18 to 55 years.
• Undergoing any intrauterine device (IUD) insertion.
• English-speaking participants.
• Ability to use an inhaler device.
• Willing to receive a cervical block for their IUD insertion

You may not qualify if:

• Inability to provide informed consent.
• Confirmed pregnancy.
• Use of pain medication other than NSAIDs or acetaminophen (e.g., opioids, benzodiazepines, muscle relaxants) within 24 hours prior to the intervention.
• Use of cannabis within 24 hours prior to the intervention.
• Administration of misoprostol within 24 hours prior to the intervention.
• Altered level of consciousness due to any cause, including head injury, drugs, or alcohol.
• History of severe adverse reactions to Penthrox (methoxyflurane) or other halogenated anesthetic agents, or to any ingredient in the formulation (including non-medicinal ingredients or container components).
• Anatomical variance, such as distorted uterine cavity, bicornuate uterus, uterus didelphys, or cervical stenosis.
• Clinically significant renal and/or liver impairment.
• Known or genetic susceptibility to malignant hyperthermia.
• Clinically evident hemodynamic or cardiovascular instability, or respiratory depression.
• Not NPO according to hospital guidelines.

Sponsors & Collaborators

• Women's College Hospital: lead

Study Sites (1)

Women's College Hospital

Toronto, Ontario, M5S 1B2, Canada

RECRUITING

MeSH Terms

Interventions

Methoxyflurane; Sodium Chloride

Intervention Hierarchy (Ancestors)

Ethyl Ethers; Ethers; Organic Chemicals; Methyl Ethers; Chlorides; Hydrochloric Acid; Chlorine Compounds; Inorganic Chemicals; Sodium Compounds

Study Officials

• Lauren Scott, NP

  Women's College Hospital

  PRINCIPAL INVESTIGATOR

• Karim Ladha, MD

  Women's College Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Didem Bozak

CONTACT

6473814051; didem.bozak@wchospital.ca

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, OUTCOMES ASSESSOR
• Masking Details: As noted above, only the individual preparing the intervention will be aware of allocation assignment. The participant, IUD provider, anesthesia provider and outcomes assessors will be blinded to minimize bias.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: This study is designed as a double-blind, placebo-controlled randomized controlled trial (RCT) conducted at The Bay Centre for Birth Control Clinic at Women's College Hospital (WCH). The intervention will occur over a single study visit, with data collected at baseline, immediately prior to the procedure, and following the procedure using quantitative survey instruments. Participant recruitment is planned over an 18-month period.

Study Record Dates

• First Submitted: November 27, 2025
• First Posted: December 19, 2025
• Study Start: April 1, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): February 1, 2027
• Last Updated: April 27, 2026

Record last verified: 2026-04

Locations

CA (1)