Methoxyflurane for IUD Insertion and Endometrial Biopsy

Launched by MOUNT SINAI HOSPITAL, CANADA · Jun 27, 2025

Keywords

ClinConnect Summary

This clinical trial is studying whether using a small amount of inhaled Methoxyflurane (a medicine you breathe in through a special device called a Penthrox inhaler) can help reduce pain during two common procedures: inserting an intrauterine device (IUD), which is a form of birth control, and taking an endometrial biopsy, which is a small tissue sample from the lining of the uterus. The study compares Methoxyflurane to a placebo (a harmless saline solution) to see if it really makes a difference in how much pain patients feel.

Women between 18 and 65 years old who are having either an IUD insertion (if they have never given birth before) or an endometrial biopsy may be eligible to join. Participants must speak English and have someone to drive them home after the appointment. During the study, each woman will be randomly given either the Methoxyflurane or the placebo to breathe in just before the procedure. Afterward, they will be asked to rate their pain using a simple scale. People taking strong pain medicines, breastfeeding, or with certain health issues won’t be able to join. This study is currently looking for volunteers and aims to find a better way to make these procedures more comfortable.

Gender

FEMALE

Eligibility criteria

• • 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