Recruiting

Methoxyflurane

Sponsor:

Women's College Hospital

Code:

NCT07295054

Conditions

IUD

Eligibility Criteria

Sex: Female

Age: 18 - 55

Healthy Volunteers: Not accepted

Interventions

Methoxyflurane

Saline

Study Details

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

Study ID

NCT07295054

Start date

Apr 27, 2026

Status verified date

May, 2026

Completion date

Feb, 2027

Anticipated

Primary completion date

Dec, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Female

Age: 18 - 55

Healthy Volunteers: Not accepted

Inclusion Criteria:

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

Exclusion Criteria:

1. Inability to provide informed consent.
2. Confirmed pregnancy.
3. Use of pain medication other than NSAIDs or acetaminophen (e.g., opioids, benzodiazepines, muscle relaxants) within 24 hours prior to the intervention.
4. Use of cannabis within 24 hours prior to the intervention.
5. Administration of misoprostol within 24 hours prior to the intervention.
6. Altered level of consciousness due to any cause, including head injury, drugs, or alcohol.
7. 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).
8. Anatomical variance, such as distorted uterine cavity, bicornuate uterus, uterus didelphys, or cervical stenosis.
9. Clinically significant renal and/or liver impairment.
10. Known or genetic susceptibility to malignant hyperthermia.
11. Clinically evident hemodynamic or cardiovascular instability, or respiratory depression.
12. Not NPO according to hospital guidelines.

Study Design

Enrollment

110 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Intervention Group

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.

placebo comparator: Placebo Group

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.

Interventions

Methoxyflurane

3 mL of Methoxyflurane via a handheld inhaler

Saline

3 mL of Normal Saline via an identical placebo handheld inhaler

Primary outcome measure

  • Procedural pain intensity [ Time Frame: 20 minutes after post-procedure ]

Central Contacts and Locations

Central contacts

Didem Bozak

6473814051didem.bozak@wchospital.ca

Locations

Women's College Hospital

Recruiting

Toronto, Ontario, Canada, M5S 1B2

Contacts

Didem Bozak

416-323-6008didem.bozak@wchospital.ca

More Information

Sponsor

Women's College Hospital

Last update posted

May 11, 2026

Last verified

May, 2026

Keywords

  • Methoxyflurane
  • Penthrox

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Women's College Hospital on 2026-05-11.