What is the recommended dosing and administration of Penthrox (methoxyflurane) and Ativan (lorazepam) for an adult woman undergoing intrauterine device insertion?

Penthrox and Ativan for IUD Insertion

For IUD insertion, use lorazepam (Ativan) 1-2 mg sublingually 20-30 minutes before the procedure for anxiolysis, but note that Penthrox (methoxyflurane) is not currently recommended in published guidelines for this indication. 1

Lorazepam (Ativan) Dosing

According to the most recent 2025 American Journal of Obstetrics and Gynecology guidelines on IUD insertion pain management, oral midazolam 10 mg taken 30-60 minutes beforehand is the preferred benzodiazepine due to its fast onset, short half-life (1.5-2.5 hours), and favorable safety profile. 1

Alternative benzodiazepine options include:

• 1-2 mg sublingual lorazepam taken 20-30 minutes before the procedure 1
• 5-10 mg oral diazepam taken 20-30 minutes beforehand 1

Critical Caveats for Benzodiazepine Use:

• Benzodiazepines do not directly reduce pain—they only alleviate anxiety 1
• No studies have specifically investigated oral anxiolytics for reducing IUD placement pain 1
• Cannot be combined with opioids (such as tramadol) due to safety concerns 1
• Patient may need transportation to and from the appointment 1

Penthrox (Methoxyflurane) Considerations

Penthrox is NOT mentioned in the 2025 best practice guidelines for IUD insertion pain management, which is the highest quality and most recent evidence available for this specific procedure. 1

However, research evidence shows:

• Penthrox has been studied for outpatient hysteroscopy and other intrauterine procedures with mixed results 2
• In a 2024 observational study of 122 women undergoing intrauterine procedures, 95.1% completed their procedure with Penthrox, and 91% would use it again 2
• Expected pain was 6.0/10 versus actual experienced pain of 5.1/10 2
• A 2025 systematic review found variable results when Penthrox was compared to placebo or IV sedation for outpatient procedures, with no consistent benefit demonstrated 3
• Penthrox is licensed for emergency trauma pain, not elective gynecological procedures 4

Recommended Evidence-Based Approach for IUD Insertion

The 2025 guidelines recommend a multimodal approach prioritizing:

1. Pre-procedural Analgesics (1-2 hours before)

• Naproxen 550 mg orally (preferred NSAID) 1
• OR Ketorolac 20 mg orally or 30 mg IM 1

2. Anxiolytic (if significant anxiety)

• Midazolam 10 mg orally 30-60 minutes before (first choice) 1
• OR Lorazepam 1-2 mg sublingual 20-30 minutes before (alternative) 1

3. Local Anesthesia (during procedure)

• Intracervical block (ICB): 3.6-4 mL of 2% lidocaine at 3,6,9, and 12 o'clock positions before tenaculum placement 1
• OR Paracervical block (PCB): 2 mL buffered 1% lidocaine at tenaculum site, then remaining anesthetic at 4 and 8 o'clock positions 1
• OR Topical anesthesia: 4-5 g EMLA cream applied to cervix with 5-10 minute wait time 1

4. Post-procedure

• Scheduled NSAIDs with food for 24-72 hours 1

Clinical Algorithm

For a patient requesting anxiolysis for IUD insertion:

1. Assess anxiety level and pain concerns
2. Prescribe pre-procedural NSAID: Naproxen 550 mg to take 1-2 hours before
3. If significant anxiety: Add midazolam 10 mg (or lorazepam 1-2 mg sublingual as alternative) to take 30-60 minutes (or 20-30 minutes for lorazepam) before
4. Arrange transportation if benzodiazepine prescribed
5. Plan intraprocedural local anesthesia (ICB or PCB preferred over topical alone)
6. Prescribe scheduled NSAIDs for 24-72 hours post-procedure

Penthrox should not be routinely used for IUD insertion as it lacks guideline support and has inconsistent evidence for gynecological procedures. If considering off-label use, recognize this represents unvalidated practice without established safety or efficacy data for this specific indication.