Researchers tested whether a common anesthetic drug called lidocaine could help patients recover their bowel function faster after colon surgery. In a large study of 557 patients across 27 UK hospitals, half received lidocaine through an IV during surgery while the other half received a placebo (fake treatment). Three days after surgery, about 57% of the lidocaine group and 59% of the placebo group had recovered normal bowel function. The results showed no meaningful difference between the groups, meaning lidocaine didn’t help patients recover faster. The study also found no differences in pain, hospital stay length, or overall recovery quality between the two groups.

The Quick Take

  • What they studied: Whether giving patients an anesthetic drug called lidocaine through an IV during colon surgery helps their digestive system start working again faster after the operation
  • Who participated: 557 adult patients scheduled for minimally invasive (keyhole) colon surgery at 27 hospitals across the United Kingdom. Patients were randomly assigned to receive either lidocaine or a placebo (salt water) during surgery.
  • Key finding: Lidocaine made no difference in bowel recovery. About 57% of patients who received lidocaine and 59% who received placebo had recovered bowel function by day 3 after surgery—a difference of less than 2% that could easily be due to chance.
  • What it means for you: If you’re having colon surgery, you shouldn’t expect lidocaine to speed up your recovery time. However, this doesn’t mean the surgery itself is unsafe or that other recovery methods won’t help. Talk to your surgical team about evidence-based ways to support your recovery.

The Research Details

This was a large, well-designed study called a randomized controlled trial, which is considered one of the best ways to test if a treatment works. Researchers enrolled 590 patients scheduled for minimally invasive colon surgery at 27 different hospitals across the UK. Patients were randomly assigned (like flipping a coin) to receive either lidocaine or a placebo (fake treatment) through an IV during surgery. Neither the patients, doctors, nor researchers knew who received which treatment until the study ended—this is called being “blinded” and helps prevent bias.

Patients in the lidocaine group received a starting dose of the drug when they fell asleep for surgery, then continued receiving it through an IV for 6 to 12 hours after surgery (depending on hospital setup). The placebo group received the same-looking salt water solution on the same schedule. Researchers tracked how quickly patients’ bowels started working again, measured their pain levels, checked their quality of life, and counted any side effects or complications.

This study design is important because previous smaller studies had suggested lidocaine might help, but those studies weren’t large enough to be completely reliable. By testing 557 patients across many hospitals, this study provides much stronger evidence about whether the treatment actually works in real-world conditions. The fact that patients, doctors, and researchers didn’t know who got the real drug helps ensure the results weren’t influenced by expectations or bias.

This study has several strengths: it was large (557 patients), included multiple hospitals across the UK, used proper randomization, kept everyone blinded to treatment assignment, and was funded by an independent government health research organization. The researchers also looked at whether the treatment worked differently for different groups of patients (younger vs. older, men vs. women, different surgery types) and found no benefits in any subgroup. The main limitation is that patients received relatively short infusions of lidocaine (6-12 hours) compared to what some earlier small studies used, so we can’t completely rule out that longer infusions might work differently.

What the Results Show

The main finding was that lidocaine did not help patients recover bowel function faster. The study measured bowel recovery as the ability to eat food and pass gas or stool by day 3 after surgery. In the lidocaine group, 160 out of 279 patients (57.3%) had recovered by day 3. In the placebo group, 164 out of 278 patients (59%) had recovered by day 3. This 1.9% difference is so small it could easily be due to chance rather than the drug actually working.

The researchers also looked at earlier signs of bowel recovery (like passing gas alone) and found no meaningful differences between groups. About 40% of patients in both groups still hadn’t recovered bowel function by day 3, showing that delayed bowel recovery is a common problem even with modern keyhole surgery techniques.

When researchers examined specific subgroups—such as younger versus older patients, men versus women, or patients who received 6 hours versus 12 hours of the drug—they found no benefits of lidocaine in any of these groups. This suggests the lack of benefit wasn’t due to the drug working better for certain types of patients.

Beyond bowel recovery, the study measured many other important outcomes and found no differences between groups: pain levels were similar, quality of life measures were the same, hospital stay length was comparable, and the need for pain medications and anti-nausea drugs was equivalent. There were no serious safety concerns—adverse events were rare and evenly distributed between the lidocaine and placebo groups. The study also found no difference in 30-day or 90-day mortality rates, unplanned hospital readmissions, or total healthcare costs between the two groups.

This study is important because earlier, smaller studies had suggested lidocaine might help speed bowel recovery after surgery. However, those studies were limited in size and design. The ALLEGRO trial is much larger and more rigorous, and it contradicts the earlier findings. This is a good example of why large, well-designed studies are needed to confirm whether treatments that look promising in smaller studies actually work in real-world practice. The results suggest that the earlier positive findings may have been due to chance, bias, or differences in how the studies were conducted.

The main limitation is that patients in this study received relatively short infusions of lidocaine (6-12 hours during and shortly after surgery), while some earlier studies used longer treatment periods. It’s possible that longer infusions might work differently, though this seems unlikely based on how the drug works in the body. Another consideration is that the study focused on minimally invasive (keyhole) surgery, so results might not apply to traditional open colon surgery. Finally, the study was conducted in UK hospitals, so results may reflect UK surgical practices and patient populations.

The Bottom Line

Based on this high-quality evidence, lidocaine infusion during colon surgery is not recommended as a way to speed bowel recovery. The study found no benefit and no cost savings. Instead, focus on evidence-based recovery methods recommended by your surgical team, such as early mobilization (getting out of bed), appropriate pain control, and gradual return to eating. If you’re having colon surgery, discuss with your surgeon what proven strategies they use to support recovery.

This finding matters most for patients scheduled for minimally invasive colon surgery and their surgical teams. Surgeons can use this evidence to avoid unnecessary medication that doesn’t help patients recover faster. Patients should know that if lidocaine is offered as a recovery aid, the evidence doesn’t support its use. However, this doesn’t change the safety or necessity of the surgery itself or other aspects of surgical care.

Bowel function recovery typically takes several days after colon surgery regardless of whether lidocaine is used. In this study, about 60% of patients recovered by day 3, with the remaining 40% recovering over the following days. Individual recovery times vary based on factors like age, overall health, and the extent of surgery. Don’t expect any medication to dramatically speed this process—recovery takes time.

Want to Apply This Research?

  • If you’re preparing for or recovering from colon surgery, track your bowel function recovery daily by noting when you first pass gas, when you can tolerate clear liquids, and when you return to solid foods. Record these milestones along with your pain level (0-10 scale) and activity level (time out of bed) to monitor your overall recovery progress.
  • Work with your surgical team on proven recovery strategies: get out of bed and walk as soon as cleared by your doctor, follow the recommended eating schedule (starting with clear liquids and gradually advancing), stay hydrated, and take pain medications as prescribed. Use the app to set reminders for these activities and track compliance with your recovery plan.
  • Create a recovery timeline in the app tracking: daily bowel function status, pain levels, activity duration, food tolerance, and any complications. Compare your recovery to typical timelines provided by your surgical team. If you experience concerning symptoms (severe pain, inability to keep fluids down, fever, or no bowel function by day 5), contact your healthcare provider immediately rather than relying on the app.

This research summary is for educational purposes only and should not replace professional medical advice. The ALLEGRO trial found that lidocaine did not improve bowel recovery after colon surgery, but individual patient circumstances vary. If you are scheduled for colon surgery or have questions about your recovery, consult with your surgeon or healthcare provider about the best evidence-based approaches for your specific situation. Do not make changes to any prescribed medications or surgical plans based on this information without discussing with your medical team.