Methoxyflurane for IUD Insertion and Endometrial Biopsy

Mount Sinai Hospital, Canada

Status: Enrolling

Conditions: Intrauterine Devices; Endometrial Biopsy

Treatments: Other: Placebo Penthrox inhaler; Drug: Methoxyflurane - Penthrox

Study type: Interventional

Funder types: Other

Identifiers

NCT07046572

REB 25-0041-A

Details and patient eligibility

About

The aim of this study is to determine if 3ml of inhaled Methoxyflurane, in the form of a Penthrox inhaler, reduces pain during IUD insertion and/or endometrial biopsy. The proposed study is a double-blind, placebo-controlled RCT.

Each participant will be randomly assigned to one of two arms:

1. Intervention (3ml of Methoxyflurane via a Penthrox inhaler)
2. Placebo (3ml of normal saline via an identical placebo Penthrox inhaler)

The primary outcome is global pain score, which will be patient-reported by the 100 mm Visual Analogue Scale (VAS) 5-minutes following the procedure (endometrial biopsy or IUD insertion).

Enrollment: 174 estimated patients

Sex: Female

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion 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

Trial design

Primary purpose: Other

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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174 participants in 2 patient groups, including a placebo group

3ml of Methoxyflurane

Experimental group

Description:

3ml of Methoxyflurane via a Penthrox inhaler

Treatment:

Drug: Methoxyflurane - Penthrox

3ml of normal saline

Placebo Comparator group

Description:

3ml of normal saline via an identical placebo Penthrox inhaler

Treatment:

Other: Placebo Penthrox inhaler