Topical Magnesium Sulfate Versus Peritonsillar Bupivacaine for Post-Tonsillectomy Pain Relief in Children

August 7, 2026 updated by: Abd El-Rahman Ahmed Aboulwafa, Assiut University

Topical Magnesium Sulfate Versus Peritonsillar Bupivacaine Infiltration for Post-Tonsillectomy Analgesia: A Prospective, Randomized Trial

Tonsillectomy (tonsil removal) is a very common surgery for children, but it often causes significant throat and ear pain afterward. Doctors usually inject a numbing medicine, such as bupivacaine, into the area around the tonsils to help control this pain. However, these injections require needles, which can cause swelling, distort tissue, and slightly increase the risk of bleeding or infection, and the pain relief typically only lasts for about 4 to 6 hours.

This study is investigating a needle-free alternative to see if it provides effective pain relief. The researchers are testing a medication called magnesium sulfate, which blocks certain pain receptors and can be applied directly to the surgical site using a soaked gauze pad instead of a needle injection.

The main goal of this clinical trial is to compare how well topical magnesium sulfate relieves pain compared to standard bupivacaine injections in children undergoing tonsillectomy.

The study will include 40 children between the ages of 8 and 15 years old. During the surgery, while under general anesthesia, half of the children will receive the topical magnesium sulfate pad applied to the surgical area for 5 minutes, and the other half will receive the standard bupivacaine injection. After the surgery, researchers will measure the children's pain levels using visual pain scales featuring faces and numbers. They will also track how much extra pain medication the children need, how well their surgical wounds heal, and if they experience any adverse effects.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Postoperative pain following tonsillectomy is a primary cause of morbidity in the pediatric population, frequently leading to "tonsillectomy distress syndrome," which is characterized by severe odynophagia, referred otalgia, and psychological distress. The underlying pathophysiology of this pain is complex, involving both mechanical trauma to the pharyngeal constrictor muscles and the chemical irritation of the vagus and glossopharyngeal nerve endings.

While perioperative analgesia is traditionally managed with local anesthetic infiltration, such as bupivacaine, its analgesic efficacy is typically limited to a short duration of 4 to 6 hours. Furthermore, the physical act of needle infiltration can induce tissue edema, distort surgical planes, and potentially elevate the risk of postoperative complications, including infection and hemorrhage.

Recent advancements in pain management have highlighted the role of N-methyl-D-aspartate (NMDA) receptors in peripheral tissues, presenting new avenues for non-invasive analgesia. Magnesium sulfate serves as an NMDA receptor antagonist by blocking its calcium channel in a voltage-dependent manner. This trial investigates whether applying magnesium sulfate topically to the tonsillar fossa can provide effective postoperative analgesia without the inherent risks associated with needle infiltration.

To ensure procedural standardization across the study, all tonsillectomies in this prospective, randomized trial will be performed utilizing a cold dissection technique under general anesthesia. Postoperatively, patients will be systematically evaluated to assess pain intensity, mucosal healing via a 5-point fibrin and epithelialization grading scale, and the overall requirement for rescue analgesics.

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Phase 4

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

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Pediatric patients aged 8-15 years undergoing elective tonsillectomy.

Exclusion Criteria:

  • Patients younger than 8 years or older than 15 years.
  • Known allergy to magnesium sulfate or bupivacaine.
  • Pre-existing neurological disorders (for example, neuromuscular diseases, epilepsy) that could affect pain perception or magnesium metabolism.
  • Pre-existing cognitive impairment or developmental delay affecting pain assessment.
  • Chronic pain syndromes or regular use of analgesics.
  • Coagulopathy or bleeding 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: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group A: Topical Magnesium Sulfate
Participants in this group will have a sterile gauze soaked in 5 mL of 20% magnesium sulfate (2 mg/kg) packed into the tonsillar fossa for 5 minutes post-hemostasis.
Drug: Magnesium Sulfate
Topical application via a sterile gauze soaked in 5 mL of 20% magnesium sulfate (2mg/kg) packed into the fossa for 5 minutes post-hemostasis.
Active Comparator: Group B: Peritonsillar Bupivacaine
Participants in this group will receive an injection of 2 mL of 0.25% bupivacaine directly into the peritonsillar space, specifically at the superior, middle, and inferior poles.
Drug: Bupivacaine
Peritonsillar infiltration involving the injection of 2 mL of 0.25% bupivacaine into the superior, middle, and inferior poles of the peritonsillar space.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postoperative Pain Intensity Assessed by the Wong-Baker FACES Pain Rating Scale
Time Frame: At 24 hours postoperatively
The Wong-Baker FACES Pain Rating Scale is a visual assessment tool that features a series of six cartoon faces showing different emotional expressions to help pediatric patients communicate their pain levels. The scale ranges from a minimum score of 0, which corresponds to a happy, smiling face meaning "No Hurt," to a maximum score of 10, which corresponds to a sad, crying face meaning "Hurts Worst". Higher scores on this scale indicate greater pain intensity, reflecting a worse patient outcome.
At 24 hours postoperatively

Collaborators and Investigators

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

Sponsor

Assiut University

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 (Estimated)

September 1, 2026

Primary Completion (Estimated)

September 1, 2027

Study Completion (Estimated)

October 1, 2027

Study Registration Dates

First Submitted

August 7, 2026

First Submitted That Met QC Criteria

August 7, 2026

First Posted (Actual)

August 12, 2026

Study Record Updates

Last Update Posted (Actual)

August 12, 2026

Last Update Submitted That Met QC Criteria

August 7, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Topical MgSO4 vs Bupivacaine

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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