Inhaled methoxyflurane for pain during IUD insertion and endometrial biopsy.

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This double-blind, placebo-controlled randomized trial assigns adults undergoing IUD insertion (nulliparous for IUD) or endometrial biopsy to receive either 3 mL inhaled methoxyflurane via a Penthrox inhaler or 3 mL normal saline via an identical placebo inhaler. The primary outcome is patient-reported global pain on a 100 mm visual analogue scale measured 5 minutes after the procedure. Key exclusions include recent opioid or benzodiazepine use, breastfeeding, chronic pain syndromes, renal or liver disease, allergy to methoxyflurane, known susceptibility to malignant hyperthermia, and certain abnormal baseline vital signs. Enrollment takes place at Mount Sinai Hospital/OPG in Toronto and participants must be English-speaking and able to arrange transportation home.

Why it matters

Who can join: the full rules

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

Where it's running

• Opg
  Toronto, Ontario, Canada Recruiting

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.