Efficacy of Inhaled Methoxyflurane (Penthrox) as Adjunct for Urologic Procedures Under Local Anesthetic: A Pilot Study

We wish to perform a prospective randomized controlled pilot study at the Men's Health Clinic and Health Science's Centre to assess whether or not the use of Penthrox as an adjunct to LA is associated with improved pain tolerance and anxiety levels than local anesthetic alone

Study Overview

• Status: Completed
• Conditions: Anesthesia, Local; Spermatocele; Scrotum Disease; Hydrocele Male; Scrotal Hematocele
• Intervention / Treatment: Drug: Methoxyflurane; Other: Control

Detailed Description

This non-blinded, randomized controlled trial is to be conducted at both the Men's Health Clinic and Health Sciences Centre in Winnipeg, Manitoba. All eligible patients between the ages of 18-65, undergoing andrology and male infertility under local anesthetic or select endourology procedures under loco-sedation, will be invited to participate in the study. Patients will be excluded if; history of substance use disorder, history renal impairment, history of liver dysfunction, previous hypersensitivity to Penthrox or related agents, personal or family history of malignant hypothermia. They will be randomly assigned in a 1:1 ratio using a computer-generated random list. For penoscrotal cases, patient will be randomized to Penthrox + local infiltration of 50/50 lidocaine and bupivacaine mixture vs local infiltration alone. For select endourology procedures, patients will be randomized to Penthrox + topical local anesthetic vs IV sedation + topical anesthetic. Participants may begin using the Penthrox 10 minutes prior to procedure start given its median time of onset of 5 minutes. In the post-operative recovery area, patient will be asked to complete a questionnaire related to pain and anxiety of procedure.

Baseline characteristics such as age, use of analgesics, prior history of procedure under loco-sedation, history of chronic pain, baseline pain level (Brief Pain Inventory), pre-procedural anxiety (State Trait Anxiety Inventory) will be collected.

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Phase 2

Contacts and Locations

Study Locations

• Canada
  • Manitoba
    • Winnipeg, Manitoba, Canada, R3K 1M3
      • Men's Health Clinic

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adult patients undergoing hydrocelectomy, spermatocelectomy, epididymectomy, testicular biopsy, scrotal lesion or cyst excision under local anesthesia alone will be included.

Exclusion Criteria:

• Patients will be excluded if their procedure was to be performed with sedatives (e.g., inhaled nitrous oxide gas, oral, or IV sedation) or did not provide consent to be randomized

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention arm-Penthrox; Participants can begin using penthrox 10 minutes prior to procedure start, given its median onset time of 5 minutes	Drug: Methoxyflurane; Penthrox is a brand name for a drug called methoxyflurane. It is an inhaled analgesic (pain-relieving) agent used primarily for the relief of moderate to severe pain, typically in emergency medical situations or during minor medical procedures. Penthrox is administered by inhaling the vapors through a hand-held inhaler device. It acts quickly to provide pain relief and has a relatively short duration of action.
Placebo Comparator: Control arm; Patients in the control arm will only receive local infiltration.	Other: Control; This intervention will be the control group, only receiving local infiltration.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain with local anesthetic infiltration	Using a visual analogue pain scale [range 0-10; 0 = no pain, 10 = maximal pain], pain will be assessed as reported by the patient when the local anesthetic injection is administered	Immediately post-infiltration, intraoperatively
Procedural pain	Using a visual analogue pain scale [range 0-10; 0 = no pain, 10 = maximal pain], pain will be assessed as reported by the patient post-operatively to determine their pain	Immediately post-operation

Collaborators and Investigators

• Sponsor: University of Manitoba

Study record dates

Study Major Dates

• Study Start (Actual): April 17, 2024
• Primary Completion (Actual): November 27, 2024
• Study Completion (Actual): December 19, 2024

Study Registration Dates

• First Submitted: February 16, 2024
• First Submitted That Met QC Criteria: September 23, 2025
• First Posted (Estimated): September 25, 2025

Study Record Updates

• Last Update Posted (Estimated): September 25, 2025
• Last Update Submitted That Met QC Criteria: September 23, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Pathologic Processes; Genital Diseases, Male; Male Urogenital Diseases; Pathological Conditions, Anatomical; Hemorrhage; Cysts; Pathological Conditions, Signs and Symptoms; Spermatocele; Hematocele; Organic Chemicals; Ethers; Methyl Ethers; Ethyl Ethers; Methoxyflurane
• Other Study ID Numbers: HS26348

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes