Researchers at the Medical University of South Carolina have discovered that a drug already approved by the U.S. Food and Drug Administration may help patients feel less pain after surgery while also reducing the need for opioid painkillers.
The drug, called N-acetylcysteine, or NAC, has been used for years for other medical purposes, but scientists now believe it may also become a safer option for managing pain after operations.
Pain after surgery is a major problem for many patients. Doctors often prescribe opioid medicines such as oxycodone or morphine to control severe pain after operations. While these medicines can be effective, they also come with serious risks.
Opioids can cause drowsiness, nausea, constipation, breathing problems, dependence, and addiction. Over time, some patients may need larger doses to get the same pain relief, which increases the risk of misuse and overdose.
Because of these concerns, researchers around the world are searching for safer ways to manage pain without relying so heavily on opioids. The team at the Medical University of South Carolina believes NAC could become part of the solution.
The research focused on patients who underwent spinal surgery, which is often associated with significant pain during recovery. The scientists found that patients who received NAC during surgery reported less pain afterward and needed fewer opioid medications compared to patients who received a placebo treatment.
The study was led by Dr. Sylvia Wilson and Dr. Michael Scofield. Dr. Wilson has spent years studying safer approaches to pain management, especially treatments that could reduce the need for opioids after surgery.
Dr. Scofield has a strong background in researching how NAC affects the brain, particularly in areas linked to pain, addiction, and drug dependence.
Their combined expertise helped create the clinical study. During the trial, patients undergoing spinal surgery were randomly assigned to receive either NAC or a placebo saline solution during the operation.
The researchers then monitored how much pain medicine the patients requested after surgery and how quickly they asked for it.
The results were encouraging. Patients who received NAC required 19% fewer opioid doses than those in the placebo group. In addition, patients given NAC waited longer before requesting their first pain medication after surgery.
This suggests that NAC may continue helping with pain relief even after the drug itself is no longer strongly active in the body.
Researchers found this especially interesting because it matched earlier findings from addiction research. Dr. Scofield had previously studied NAC in relation to heroin addiction and found that the drug appeared to create lasting changes in the brain that continued after treatment.
NAC itself is not a new medicine. It has already been approved by the FDA for other medical uses, including treating acetaminophen overdose and helping break up mucus in patients with certain lung conditions.
Because the drug is already known to doctors and has an established safety history, researchers hope it may move more quickly through the development process for pain management compared to a completely new drug.
Scientists believe NAC may work by affecting glutamate, an important chemical messenger in the brain and nervous system. Glutamate plays a major role in pain signaling, learning, memory, and addiction. By helping regulate glutamate levels, NAC may reduce abnormal brain activity linked to pain and cravings.
The study’s findings are important because pain after surgery can sometimes lead to long-term opioid use. Some patients continue taking opioids for weeks or months after operations, increasing the risk of dependence. A treatment that lowers opioid use during recovery could help reduce this risk and improve patient safety.
Encouraged by the early success of the spinal surgery study, the research team is now expanding their work to other types of operations. Their next clinical trial is focusing on minimally invasive hysterectomies, a common surgical procedure for women.
The researchers hope this broader study will help confirm whether NAC can safely reduce pain across different surgeries and patient groups.
Changing medical practice, however, takes time. Doctors and hospitals need strong scientific evidence before adopting new treatments as standard care. This means larger clinical trials will still be needed to fully confirm NAC’s effectiveness and safety for post-surgical pain management.
Dr. Wilson and her colleagues remain optimistic. They believe NAC could eventually become a valuable tool for doctors trying to reduce opioid use while still giving patients effective pain relief.
If future studies continue to produce positive results, NAC may help improve recovery experiences for many people after surgery. Patients may be able to heal with less discomfort, fewer opioid side effects, and lower risks of addiction.
The findings also highlight the importance of exploring new uses for older medicines. Sometimes a drug already approved for one condition may unexpectedly prove helpful for another medical problem, saving years of development time and offering patients faster access to safer treatments.
If you care about pain, please read studies that vegetarian women have higher risk of hip fracture, and these vitamins could help reduce bone fracture risk.
For more information about wellness, please see recent studies that Krill oil could improve muscle health in older people, and Jarlsberg cheese could help prevent bone thinning disease.
The study was published in the scientific journal Pain Management.
Copyright © 2026 Knowridge Science Report. All rights reserved.
