Topical Lidocaine 23%/Tetracaine 7% Ointment for Post-Hemorrhoidectomy Analgesia: A Randomized Controlled Trial

June 30, 2026 updated by: Felipe Bellolio Roth, Pontificia Universidad Catolica de Chile

Efficacy and Safety of Topical Lidocaine 23%/Tetracaine 7% Ointment Versus Placebo for Post-Hemorrhoidectomy Pain: A Double-Blind Randomized Controlled Trial

The goal of this clinical trial is to learn if a topical ointment containing two local anesthetics (lidocaine 23% and tetracaine 7%) can reduce pain after hemorrhoid surgery in adults. The main questions it aims to answer are:

  • Does the ointment lower post-defecation pain movements in the first 10 days after surgery?
  • Does the ointment lower overall daily pain in the 10 days after surgery?
  • Does the ointment reduce the need for rescue pain medication (tramadol)?

Researchers will compare the lidocaine/tetracaine ointment to a placebo (a look-alike ointment that contains no active drug) to see if the active ointment works better to reduce pain after hemorrhoid surgery.

Participants will:

  • Apply the ointment or placebo to the anal area every 12 hours for 10 days after surgery
  • Rate their pain on a scale from 0 to 10 each day, including pain after bowel movements/defecation
  • Record how many times they take rescue pain medication each day
  • Receive check-in calls/mesages from the research team after surgery

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Background

Hemorrhoidectomy is the most effective surgical treatment for advanced hemorrhoidal disease, but it is associated with significant postoperative pain, particularly during bowel movements. Standard multimodal analgesia regimens, including scheduled non-steroidal anti-inflammatory drugs, acetaminophen, and opioid rescue doses, often provide incomplete relief, especially during defecation. Topical local anesthetics have been explored as adjuvant analgesic agents in this setting, but commercially available formulations use low concentrations (typically 2-2.5%) that may limit their efficacy. High-concentration compounded formulations containing lidocaine 23% and tetracaine 7% have demonstrated an adequate pharmacokinetic safety profile in other clinical settings, but had not been evaluated in proctological surgery prior to this trial.

Study Design

This was a single-center, double-blind, placebo-controlled randomized controlled trial (RCT) conducted at a private academic institution in Santiago, Chile. Participants were randomized in a 1:1 ratio to receive either active ointment (lidocaine 23%/tetracaine 7%) or an identical-appearing placebo ointment. Randomization was performed using a computer-generated sequence with allocation concealment via an encrypted randomization. Both participants and the surgical team were blinded to treatment allocation throughout the follow-up period. The ointments were prepared and labeled by an independent compounding pharmacy, and were identical in color, texture, and packaging.

Intervention

Participants in the intervention group applied approximately 2 g of the lidocaine 23%/tetracaine 7% ointment to the perianal area every 12 hours, beginning on the day of surgery (postoperative day 0) and continuing through postoperative day 10. Participants in the control group applied an identical-appearing placebo ointment following the same schedule. All participants received a standardized perioperative analgesic protocol consisting of scheduled oral ketorolac and acetaminophen, with oral tramadol (25 mg per dose) as rescue analgesia available on demand. Surgical technique was standardized across participating surgeons; trainees operated under direct supervision of board-certified colorectal surgeons.

Outcomes and Measurements

Pain was assessed using a 0-10 visual analogue scale (VAS). Two pain dimensions were recorded daily by participants in a structured paper diary. Post-defecatory pain was recorded as a VAS score immediately after each bowel movement; on days with more than one bowel movement, the mean score was used; on days without a bowel movement, no score was recorded for this dimension. Mean daily pain was recorded as the average VAS score across the entire day, noted each evening. Rescue opioid use was recorded daily as the number of tramadol doses taken. Adverse events were recorded at each follow-up contact and at the end of the 10-day period. Follow-up was conducted by a dedicated research assistant via telephone and messages. Participants were also asked to return their completed diary at the day-10 contact.

Sample Size

Sample size was calculated to detect a clinically relevant 25% reduction in post-defecatory pain, assuming a mean VAS score of 6.6 (SD 2.2), with a two-sided significance level of 0.05 and 80% power, yielding 56 evaluable participants (28 per group). Accounting for an anticipated 10% loss to follow-up, target enrollment was set at 62 patients.

Statistical Analysis

All analyses were performed on an intention-to-treat basis. Continuous variables were compared using the independent samples Student's t-test after confirming normality with the Shapiro-Wilk test and homogeneity of variance with Levene's test. The t-test with equal variances assumed was applied consistently across all time points of each outcome variable to maintain methodological consistency. Categorical variables were compared using Pearson's chi-square test. Period averages for post-defecatory pain (days 1-5 and days 1-10) were calculated as the mean of available daily scores per participant. Daily mean overall pain for the 10-day period was calculated from the pre-specified composite variable. Statistical significance was set at p < 0.05 (two-tailed). All analyses were performed using IBM SPSS Statistics version 29.

Safety Considerations

Prior to trial design, the pharmacokinetic profile of the lidocaine 23%/tetracaine 7% formulation was reviewed. Published data indicate that peak plasma lidocaine concentrations remain below the recognized toxicity threshold of 2 mcg/mL when the formulation is applied to surface areas under 250 cm². In this trial, participants applied approximately 2 g to a perianal surface area of 10-30 cm², representing a substantially lower dose than those associated with systemic toxicity. Participants with conditions associated with increased risk of local anesthetic toxicity (significant cardiovascular, cerebrovascular, or hepatic disease; seizure disorders) were excluded from enrollment. Plasma lidocaine levels were not routinely measured given the low dose used.

Study Type

Interventional

Enrollment (Actual)

74

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Chile
    • RM
      • Santiago, RM, Chile
        • Red UC Christus Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 18 years or older
  • Scheduled for elective hemorrhoidectomy
  • Recruited consecutively on the day of surgery
  • Able to provide written informed consent

Exclusion Criteria:

  • Inflammatory bowel disease
  • Immunosuppression
  • Pregnancy
  • Chronic pain requiring ongoing analgesic treatment
  • Known hypersensitivity to any of the study medications
  • Significant cardiovascular disease
  • Peripheral vascular disease
  • Cerebrovascular disease
  • Hepatic disease
  • Seizure disorders

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Lidocaine/Tetracaine Ointment
Participants applied approximately 2 g of compounded lidocaine 23%/tetracaine 7% ointment to the perianal area every 12 hours, beginning on the day of surgery (postoperative day 0) and continuing through postoperative day 10. All participants also received a standardized perioperative analgesic protocol consisting of scheduled oral ketorolac and acetaminophen, with oral tramadol 25 mg per dose available on demand as rescue analgesia.
Drug: Lidocaine 23% / Tetracaine 7% topical ointment (compounded)
Compounded topical ointment containing lidocaine 23% and tetracaine 7%, prepared by an independent compounding pharmacy. Approximately 2 g applied to the perianal area every 12 hours from postoperative day 0 through day 10.
Placebo Comparator: Placebo
Participants applied an identical-appearing placebo ointment to the perianal area every 12 hours following the same schedule as the intervention group (postoperative days 0 to 10). The placebo was prepared by the same independent compounding pharmacy and was identical in color, texture, and packaging to the active ointment. All participants also received the same standardized perioperative analgesic protocol consisting of scheduled oral ketorolac and acetaminophen, with oral tramadol 25 mg per dose available on demand as rescue analgesia.
Other: Placebo ointment
Inert topical ointment identical in appearance, color, texture, and packaging to the active intervention, prepared by the same independent compounding pharmacy. Applied following the same schedule as the active ointment

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Post-defecatory pain score during the first 10 postoperative days
Time Frame: Postoperative days 1 through 10
Self-reported post-defecatory pain intensity assessed using a 0-10 visual analogue scale (VAS), recorded by participants immediately after each bowel movement. The primary outcome is the mean of available daily post-defecatory VAS scores across postoperative days 1 through 10. On days with more than one bowel movement, the daily score represents the mean of all recordings. Days without a bowel movement are excluded from the calculation.
Postoperative days 1 through 10

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean daily pain score
Time Frame: Postoperative days 1 through 10
Mean overall daily pain intensity assessed using a 0-10 VAS, recorded each evening by participants as a global rating of pain experienced throughout the day, across postoperative days 1 through 10.
Postoperative days 1 through 10
Cumulative rescue opioid consumption
Time Frame: Postoperative days 1 through 10
Total number of tramadol 25 mg doses taken over the 10-day follow-up period, recorded daily in the pain diary. Missing daily entries are treated as zero doses.
Postoperative days 1 through 10
Adverse effects related to the study ointment
Time Frame: Postoperative days 0 through 10
Incidence and nature of adverse events potentially attributable to the topical ointment, including local reactions (pruritus, burning, skin irritation) and systemic symptoms (nausea, headache, dizziness). Recorded at each follow-up contact on postoperative days 1, 3, 6, and 10.
Postoperative days 0 through 10
Postoperative complications within 30 days
Time Frame: 30 days postoperatively
Incidence of surgical complications within 30 days of hemorrhoidectomy, including bleeding, infection, urinary retention, and unplanned return to the operating room.
30 days postoperatively
Mean post-defecatory pain score during postoperative days 1-5
Time Frame: Postoperative days 1 through 5
Mean post-defecatory VAS score (0-10) calculated across postoperative days 1 through 5, as a pre-specified exploratory subperiod analysis.
Postoperative days 1 through 5
Mean daily pain score during postoperative days 1-5
Time Frame: Postoperative days 1 through 5
Mean overall daily VAS score (0-10) calculated across postoperative days 1 through 5, as a pre-specified exploratory subperiod analysis.
Postoperative days 1 through 5

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Pontificia Universidad Catolica de Chile

Collaborators

Sociedad Chilena de Coloproctología

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 24, 2023

Primary Completion (Actual)

October 9, 2025

Study Completion (Actual)

May 12, 2026

Study Registration Dates

First Submitted

June 30, 2026

First Submitted That Met QC Criteria

June 30, 2026

First Posted (Actual)

July 7, 2026

Study Record Updates

Last Update Posted (Actual)

July 7, 2026

Last Update Submitted That Met QC Criteria

June 30, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 220531005

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared. The institutional review board and research ethics committee that approved this study (Protocol ID: 220531005) does not authorize the export or transfer of clinical data outside the approved research context. The committee assumes no responsibility for data use beyond the scope of the original protocol and permits access to clinical data only upon formal written request and explicit authorization by the ethics committee.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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