RecruitingPhase 4NCT07295054

3 mL Inhaled Methoxyflurane for Intrauterine Device (IUD) Insertion

A Double-blind Placebo-controlled Randomized Controlled Trial (RCT) of 3 mL Inhaled Methoxyflurane for Intrauterine Device (IUD) Insertion

Sponsor

Women's College Hospital

Enrollment

110 participants

Start Date

Apr 1, 2026

Study Type

INTERVENTIONAL

Conditions

IUD

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.

Eligibility

Sex: FEMALEMin Age: 18 YearsMax Age: 55 Years

Inclusion Criteria6

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

Exclusion Criteria12

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.