A lidocaine infusion is a slow, controlled delivery of lidocaine directly into a vein through an IV line. While most people know lidocaine as the numbing agent dentists use or the ingredient in topical creams, delivering it intravenously sends it throughout the entire body, where it can reduce pain signaling on a systemic level. It’s used both during and after surgery and, increasingly, for chronic pain conditions that haven’t responded to other treatments.
How It Works in the Body
Lidocaine’s primary target is voltage-gated sodium channels, which are proteins embedded in nerve cell membranes that allow electrical signals to fire and travel. Every time you feel pain, sodium channels open in sequence along a nerve fiber, passing the signal from the injury site to the brain. Lidocaine binds to these channels one-to-one, physically blocking sodium from flowing through and interrupting that signal relay.
What makes lidocaine especially useful is that it preferentially binds to nerve channels that are already active. Channels firing rapidly (as they do in injured or inflamed tissue sending persistent pain signals) shift into a shape that lidocaine latches onto more tightly. Channels at rest, like those controlling normal sensation or heart rhythm at therapeutic doses, are largely left alone. This selectivity is why a lidocaine infusion can dampen pain without completely numbing the body.
Beyond blocking pain signals directly, intravenous lidocaine also has anti-inflammatory properties. This dual action helps explain why its benefits sometimes outlast the infusion itself, particularly in surgical recovery.
Surgical and Postoperative Use
The most established use of lidocaine infusions is during and after surgery, particularly abdominal procedures. Perioperative lidocaine infusions have been shown to decrease postoperative pain, reduce the need for opioid painkillers, speed up the return of bowel function, and shorten hospital stays. For colon surgery specifically, one clinical trial found an 18% reduction in time to first bowel movement, with patients receiving lidocaine having a bowel movement more than 24 hours earlier than those given a placebo.
Patients in that same trial also needed significantly less supplemental pain medication. This matters because opioids given after surgery are themselves a major contributor to slow gut recovery, creating a cycle where pain control and bowel function work against each other. Lidocaine infusions help break that cycle. The anti-inflammatory effects of lidocaine are thought to play a direct role in resolving postoperative ileus, the temporary paralysis of the intestines that commonly follows abdominal surgery.
Continuing the infusion for up to 24 hours after the operation appears to improve outcomes across the board: pain scores, opioid use, fatigue, bowel function, and length of stay all showed significant improvement in studies using this extended protocol. Recent reviews, however, suggest that continuing beyond about 60 minutes after leaving the recovery room may not add further benefit in all cases, so practices vary between hospitals.
Chronic Pain Applications
Lidocaine infusions are also used in pain clinics for people living with chronic pain conditions, though the evidence here is less definitive than in the surgical setting. Conditions treated include fibromyalgia, complex regional pain syndrome (CRPS), widespread chronic pain, and certain types of neuropathic pain.
A prospective analysis of 74 patients with fibromyalgia who received three or more infusions found that higher doses produced longer-lasting pain relief. Among patients with chronic widespread pain and fibromyalgia, pain intensity scores dropped significantly after treatment, with reductions in both worst pain and average pain over 24 hours. Results for other conditions like non-specific low back pain were less consistent.
In the UK, the National Institute for Health and Care Excellence (NICE) advises against offering intravenous local anesthetics for primary chronic pain outside of clinical trials, with the exception of complex regional pain syndrome. This reflects the reality that while many patients report meaningful short-term relief, the quality of evidence for long-term benefit in chronic pain remains mixed. Lidocaine infusions for chronic pain are typically offered when standard medications have failed and are part of a broader pain management plan.
What the Infusion Feels Like
During a lidocaine infusion, the most commonly reported sensations are numbness or tingling around the mouth and lips, a metallic taste, lightheadedness, and mild drowsiness. Some people experience dizziness, blurred vision, or a sense of restlessness. These effects are generally mild and transient, resolving as the infusion rate is adjusted or after the infusion ends.
For chronic pain treatment, a typical session lasts anywhere from 30 minutes to several hours depending on the protocol. You’ll be seated or reclined in a monitored setting with an IV in your arm. Surgical infusions, by contrast, begin in the operating room and may continue into the recovery period. In either case, you won’t be unconscious; this is not general anesthesia. Most people describe the experience as uneventful, with the numbness around the lips being the most noticeable sign that the medication is circulating.
Dosing and Duration
Lidocaine infusion doses are calculated based on body weight. The general approach involves an initial loading dose of 1 to 2 mg per kilogram of body weight, given over about 10 minutes to establish a therapeutic level quickly. This is followed by a continuous infusion at 1 to 2 mg per kilogram per hour. For a person weighing 70 kg (about 154 pounds), that translates to roughly 70 to 140 mg as the initial dose and the same range per hour during the infusion.
Clinical studies have used infusion rates ranging from 1.3 to 3 mg/kg/hr during surgery, with the higher end used for shorter procedures. For longer infusions, a gradual reduction in rate (roughly halving every six hours) helps minimize the risk of side effects as lidocaine accumulates in the body. The optimal dosing strategy is still not fully standardized, and protocols differ between institutions and between surgical versus chronic pain settings.
Safety Monitoring During Infusion
Because lidocaine affects nerve signaling throughout the body, including the heart, continuous monitoring is required during any infusion. At minimum, this includes continuous ECG (heart rhythm monitoring), blood pressure checks, and pulse oximetry to track oxygen levels. Consensus guidelines recommend that patients receive lidocaine infusions in a monitored care setting, not a standard ward bed.
After the infusion, vital signs including sedation level, blood pressure, heart rate, respiratory rate, and oxygen saturation are typically checked every 15 minutes for the first hour, then every 30 minutes for two hours, then hourly. A rescue medication (a fat-based emulsion that can rapidly neutralize lidocaine in the bloodstream) is kept on hand as a safety precaution during every infusion.
Risks and Warning Signs
The serious risk of any intravenous local anesthetic is systemic toxicity, known as LAST (local anesthetic systemic toxicity). This is rare at standard infusion rates but potentially life-threatening. The nervous system is affected first in about 80% of cases, with seizures occurring in up to 68% of toxicity events. Compared to some other local anesthetics, lidocaine is more likely to cause neurological symptoms than direct cardiac problems.
Early warning signs of toxicity progress in a recognizable pattern: tingling around the mouth, metallic taste, ringing in the ears, dizziness, visual disturbances, muscle twitching, and agitation. If unrecognized, these can escalate to seizures, breathing difficulty, dangerous heart rhythms, and in the most severe cases, cardiac arrest. This progression is exactly why continuous monitoring is non-negotiable. When toxicity is caught early, adjusting or stopping the infusion resolves symptoms quickly.
Who Should Not Receive One
Lidocaine infusions are contraindicated in people with certain heart conduction disorders, including severe heart block, Wolff-Parkinson-White syndrome, and Stokes-Adams syndrome (a condition involving sudden drops in heart output). Anyone with a known allergy to amide-type local anesthetics, the chemical family that includes lidocaine, should not receive an infusion.
Severe liver disease requires special caution because the liver is responsible for breaking down lidocaine. While not listed as an absolute contraindication by the FDA, impaired liver function slows lidocaine clearance and significantly raises the risk of accumulation and toxicity. Clinicians adjust dosing or avoid infusions altogether in patients with substantial liver impairment.