Summary: A 45-minute IV infusion of ketamine and lidocaine together clearly cut pain scores in patients with fibromyalgia, diabetic neuropathy and complex regional pain syndrome, a study at a clinic in Canada found.
Ketamine and lidocaine are both anesthetics. Ketamine is known to relieve pain, and lidocaine is good for numbing an area. Now a new study shows that giving them together in an infusion may help in chronic pain treatment. A clinic in Canada gave the two drugs together as an infusion over 45 minutes. Pain scores dropped clearly in patients with conditions like fibromyalgia, diabetic neuropathy, and complex regional pain syndrome. There are hundreds of ways to treat pain and countless drugs. Still, no one treatment fits everyone with chronic pain. That is because every person with chronic pain is different. The causes differ. And many of these people live with several health problems at once. These can include sciatica pain, chronic neck pain or back pain. It gets harder because many chronic pains are poorly understood. For example, we understand how arthritis works, but finding the cause of low back pain is hard. And despite much research, what causes fibromyalgia or migraine is still unclear. So it is no surprise that doctors look for new ways to help their patients. That is how researchers in Canada found that an IV infusion of lidocaine and ketamine could clearly reduce chronic pain. Note that using ketamine for chronic pain is not new. As an anesthetic, it is known to help with pain. The surprise is that adding lidocaine gave extra benefit. Lidocaine is a numbing drug used for local anesthesia or nerve blocks. But on its own as a painkiller, lidocaine plays only a small role in pain management. So these findings are new. They are among the first reports showing the benefit of pairing ketamine with lidocaine. The researchers have used this pairing in their patients since 2013. So they have a lot of data showing it works.
Does a ketamine and lidocaine infusion work for chronic pain?
The doctors at the Canadian clinic had used this pairing for years. So they decided to check how safe and effective it was. They studied the health records of 670 patients who got this treatment, with an average age of 53. Most had conditions like fibromyalgia, diabetic neuropathy, postherpetic neuralgia (nerve pain after shingles), and complex regional pain syndrome. All of these are hard-to-treat conditions with pain that will not let go. Each patient usually got three infusions, though 38% got five or more. Most patients reported real benefit. Many had been coming to the same clinic for years. Almost all reported a 30% or greater drop in pain scores. Half reported more than 75% improvement. Pain scores improved no matter the sex, age, or diagnosis. As for dose, they started with 4.5 mg/kg of lidocaine plus 10 mg of ketamine. Then they adjusted the dose to each patient’s response. They capped it at 600 mg lidocaine and 40 mg ketamine over 45 minutes. Going past this dose sharply raises the risk of side effects. These findings are striking. Lidocaine and ketamine are both common in pain care, yet no one had paired them before. But the study has limits. It did not follow patients after they left the facility. Still, the doctors are convinced the therapy gives long-term benefit, and they have reason to be. Most patients were regulars who had come to the clinic at least every two months for the last twelve years. The doctors believe the therapy works and that pairing lidocaine with ketamine is safe for chronic pain relief. It can help in chronic pain treatment and sciatica pain management. Beyond the conditions the Canadian team treated, it may also help people with cancer pain and nerve pain from chemotherapy. The pairing may also help limit opioid use.
If you are in the St. Louis area and want to know if ketamine has a role in your care, see our treatment page on ketamine for RSD, CRPS and refractory nerve pain. It covers the IV, under-the-tongue and skin cream routes. It also covers what the evidence does and does not show for each.
Frequently asked questions
Why would someone get a ketamine and lidocaine infusion?
For stubborn, hard-to-treat pain. The Canadian clinic used the pairing mostly for fibromyalgia, diabetic neuropathy, postherpetic neuralgia and complex regional pain syndrome. In all of these, pain often refuses to let go. Lidocaine does little for pain on its own, and ketamine is a known pain reliever. But together they gave extra benefit.
How long does a ketamine and lidocaine infusion take?
Each infusion runs through an IV over 45 minutes. Patients at the Canadian clinic usually got three infusions, and 38% got five or more. Many were long-term patients who came back to the clinic regularly. So the treatment was part of ongoing care, not a one-time visit.
How well does IV ketamine and lidocaine relieve pain?
In the records of 670 patients, with an average age of 53, almost everyone reported at least a 30% drop in pain scores. Half reported more than 75% improvement. Pain scores improved no matter the sex, age or diagnosis. So the benefit held across very different pain conditions.
What is the dose for a ketamine and lidocaine infusion?
The clinic started with 4.5 mg/kg of lidocaine plus 10 mg of ketamine. Then it adjusted the dose to each patient’s response. It never went above 600 mg of lidocaine and 40 mg of ketamine over the 45 minutes. Going past those limits sharply raises the risk of side effects.
How long does the pain relief last?
The study did not follow patients after they left the facility. So it cannot measure how long relief lasted. The doctors still believe the benefit is long-term, because most patients were regulars who came back at least every two months for years. The pairing may also help limit opioid use.
Dr. Gurpreet Singh Padda, MD, MBA, MHP
