NAC-REPAIR for Post-surgical Pain

November 12, 2025 updated by: University of Arizona

NAC-REPAIR: N-Acetylcysteine-facilitated Redox-Immune Modulation for Post-surgical Analgesia and Injury Recovery

This pilot asks whether peri-operative N-acetylcysteine (NAC) improves recovery after common outpatient hand/foot-ankle surgery-specifically, does NAC reduce pain and opioid use and enhance function by modulating redox-inflammatory pathways? Primary objectives are to establish feasibility (accrual, adherence, follow-up), estimate NAC vs placebo effects on pain, function, and opioid consumption, and characterize inflammatory signatures that may predict response.

Methods: a single-site, double-blind, 1:1 randomized trial (N≈80) comparing NAC 1,200 mg twice daily for 14 days (starting pre-op) vs matching placebo; daily e-diaries for POD0-14; standardized outcomes (PROMIS Pain Interference; QuickDASH or FAAM; PGIC; opioid MME); and small blood draws pre-surgery and at two follow-up visits for cytokine profiling.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

80

Phase

  • Phase 2

Contacts and Locations

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

Study Contact

  • Name: Valerio Tonelli Enrico, PT, PhD, MSCE
  • Phone Number: 17068097067
  • Email: vte@arizona.edu

Study Locations

  • United States
    • Arizona
      • Tucson, Arizona, United States, 85721
        • Banner Health
        • Contact:

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:

  • Elective outpatient hand/upper-extremity or foot/ankle surgery (single site; same-day discharge)
  • Baseline visit feasible ≤14 days pre-op
  • Can complete surveys/blood draw
  • Provides informed consent
  • Willing to follow dosing schedule and avoid restricted supplements/meds

Exclusion Criteria:

  • Allergy to NAC/capsule components □ NAC or high-dose antioxidants in past 14 days (unwilling to stop)
  • Chronic daily opioids ≥3 months or OUD/maintenance therapy □ Pregnant/breastfeeding or no contraception as applicable
  • Daily nitrates (nitroglycerin/isosorbide) □ Planned >24h admission, multistage/trauma case □ Other interventional study within 30 days
  • Unable to swallow capsules / malabsorption surgery affecting oral meds

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: N-Acetylcysteine (NAC)

Intervention: Oral N-acetylcysteine capsules, 600 mg twice daily.

Timing/Duration: Begin the evening before surgery (≤24 h pre-op) and continue through Post-op Day 14 (total 15 days; bottle overfilled to cover missed doses).

Administration: Self-administered at home; counseling at baseline dispense; pill diary + pill counts.

Concomitant care: All peri-operative care per standard of care (SoC), including multimodal analgesia; no high-dose antioxidant supplements; nitrates excluded.

Objective: Test whether peri-operative NAC improves early pain, function, and recovery via redox-immune modulation.
Drug: NAC

Intervention: Oral N-acetylcysteine capsules, 600 mg twice daily.

Timing/Duration: Begin the evening before surgery (≤24 h pre-op) and continue through Post-op Day 14 (total 15 days; bottle overfilled to cover missed doses).

Administration: Self-administered at home; counseling at baseline dispense; pill diary + pill counts.

Concomitant care: All peri-operative care per standard of care (SoC), including multimodal analgesia; no high-dose antioxidant supplements; nitrates excluded.

Objective: Test whether peri-operative NAC improves early pain, function, and recovery via redox-immune modulation.
Placebo Comparator: Placebo

Intervention: Matched inert capsules (e.g., microcrystalline cellulose), identical in size/appearance/labeling to NAC.

Timing/Duration: 600 mg-equivalent capsule count, twice daily, evening before surgery through Post-op Day 14.

Administration: Same counseling, diary, and adherence checks as NAC arm.

Concomitant care: Identical SoC allowances/restrictions as NAC arm.
Drug: NAC 0mg/day (Placebo)

Intervention: Matched inert capsules (e.g., microcrystalline cellulose), identical in size/appearance/labeling to NAC.

Timing/Duration: 600 mg-equivalent capsule count, twice daily, evening before surgery through Post-op Day 14.

Administration: Same counseling, diary, and adherence checks as NAC arm.

Concomitant care: Identical SoC allowances/restrictions as NAC arm.

Randomization/Blinding: 1:1, stratified by surgery type (upper- vs lower-extremity); double-blind (participants, investigators, assessors).

Primary comparisons: Early postoperative pain and function (e.g., PROMIS-PI/PF, QuickDASH or LEFS), opioid consumption; safety/tolerability.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
PROMIS pain interference
Time Frame: baseline; post-op (2-4 weeks); post-op (12 weeks);
Patient-Reported Outcomes Measurement Information System - Pain Interference T-score metric: mean = 50, SD = 10 Higher scores = worse outcome (greater pain interference with daily activities, social, cognitive, emotional, and physical functioning)
baseline; post-op (2-4 weeks); post-op (12 weeks);

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
PROMIS Physical Function
Time Frame: Baseline; post-op (2-4 weeks); post-op (12 weeks)
Patient-Reported Outcomes Measurement Information System Physical Function T-score metric: mean = 50, SD = 10 Higher scores = better outcome (greater ability to carry out physical activities such as mobility, self-care, and instrumental activities)
Baseline; post-op (2-4 weeks); post-op (12 weeks)
Numeric Pain Rating Scale
Time Frame: Baseline; post-op (2-4 weeks); post-op (12 weeks)
0-10: 0 = no pain, 10 = worst imaginable Higher scores = worse outcome (greater perceived pain intensity)
Baseline; post-op (2-4 weeks); post-op (12 weeks)

Collaborators and Investigators

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

Sponsor

University of Arizona

Collaborators

Banner University Medical Center

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)

January 15, 2026

Primary Completion (Estimated)

January 15, 2027

Study Completion (Estimated)

July 15, 2027

Study Registration Dates

First Submitted

November 10, 2025

First Submitted That Met QC Criteria

November 10, 2025

First Posted (Estimated)

November 13, 2025

Study Record Updates

Last Update Posted (Estimated)

November 14, 2025

Last Update Submitted That Met QC Criteria

November 12, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STUDY00007009

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.

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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