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  • Writer's pictureDr. Harold Pierre

Ketamine for Chronic Pain Management

Updated: Dec 7, 2023

Ketamine for Chronic Pain Management

If you suffer from chronic pain, you know how much it can negatively impact your quality of life. Chronic pain affects over 50 million adults in the United States alone. Unfortunately, common pain medications like NSAIDs or opioids often provide inadequate relief for many types of chronic pain. This has led to increasing interest in using ketamine for chronic pain management.

What is Ketamine and How Does It Work for Pain Management?

Ketamine is a unique medication originally approved for use as an anesthetic. In recent years, doctors have also prescribed ketamine at lower doses as an effective treatment for chronic pain, post-traumatic stress disorder, and depression.

Unlike opioid medications, ketamine works by interacting with the n-methyl-d-aspartate (NMDA) receptors in your brain and spinal cord. These NMDA receptors are involved in central sensitization - which is essentially your nervous system amplifying pain signals. When ketamine blocks a neurotransmitter called glutamate from binding with NMDA receptors, it can "reset" the nervous system to halt this amplification process and provide fast relief from chronic pain.

Ketamine also interacts with the opioid receptors in your brain. But it doesn’t cause the same type of addiction or issues with breathing suppression as opioid medications. In lower doses, ketamine can increase levels of serotonin, dopamine and act as an antidepressant. As the dose increases and other neurotransmitters become involved, ketamine modify pain processing to alleviate pain.

Ways Ketamine Therapy May Be Administered

There are several methods available for administering ketamine:

  • Intravenous ketamine infusion - This remains the most common method. Ketamine is injected into the bloodstream through an IV line. IV infusion provides rapid pain relief that may last for a few hours up to a few weeks. This route has gained popularity for treating severe depression.

  • Oral/sublingual ketamine - You can take ketamine by mouth or allow it to dissolve under your tongue. While oral ketamine has lower bioavailability, it offers longer-lasting pain relief.

  • Nasal spray - A ketamine nasal spray (Spravato) was approved by the FDA in recent years for depression. Off-label, the nasal spray is convenient to use at home to help manage breakthrough pain flares.

  • Topical - Ketamine creams or gels can be applied directly on the skin over painful areas. This provides localized pain relief without excessive systemic absorption.

  • Intramuscular injections - Although less common now, ketamine can also be injected into the muscle. It has a slower onset than IV administration but longer duration of action.

How Quickly Ketamine Works & How Long Effects Last With Different Routes:

  • Intravenous:

  • Takes effect within 1 minute

  • Lasts ~20 minutes

  • Oral:

  • Low bioavailability due to liver metabolism

  • Takes 30-45 minutes to start working

  • Lasts 4-6 hours

  • Intranasal:

  • Faster absorption than oral

  • Starts working in 15 minutes

  • Avoids first-pass liver metabolism

  • Lasts 4-6 hours

  • Overall:

  • Intravenous onset fastest

  • Oral onset slowest

  • Duration of immediate pain relief similar at 4-6 hours with all routes

  • Long term pain relief can last for weeks with the intravenous route

Evidence for Effectiveness in Various Chronic Pain Problems

On a beige background, a stethoscope and a white notepad with the inscription Ketamine. Medical concept copy

Ketamine has been studied extensively in clinical research for the treatment of many different chronic pain conditions. Ketamine can help with:

  • Neuropathic pain - Ketamine improved pain and decreased opioid requirements for conditions like diabetic neuropathy, postherpetic neuralgia, and phantom limb pain.

  • Headaches/migraines - Both IV and intranasal ketamine reduced headache pain and frequency in migraine and cluster headache sufferers.

  • Complex regional pain syndrome (CRPS) - Over 70% of CRPS patients in multiple studies had reduced pain for up to 3 months after ketamine infusions.

  • Back pain - Ketamine decreased chronic back pain and arthritis pain in several studies. Oral and nasal ketamine also helped control flares of breakthrough pain.

  • Cancer pain - It improved control of severe cancer pain and allowed lower opioid dosing. This helped opioid-tolerant patients get better relief.

  • Fibromyalgia - Ketamine provided significant pain improvement in fibromyalgia patients through its central desensitizing effects.

While more research is warranted, current evidence supports ketamine as an effective option for many different chronic pain conditions - especially those with a neuropathic or centralized pain component.

Potential Ketamine Side Effects

When used for anesthesia, ketamine can sometimes cause psychedelic side effects like hallucinations or feelings of “disconnection” from your surroundings. Often, ketamine is used for emergency surgery such as trauma or emergency c-sections where general anesthesia may be too risky. However, at the lower doses used for chronic pain management, side effects are generally mild and temporary:

  • Drowsiness

  • Confusion

  • Dizziness

  • Nausea

  • Vivid dreams

Rarely, ketamine may worsen underlying psychiatric problems like schizophrenia. It must be used very cautiously in patients with poorly controlled cardiovascular disease due to its stimulant effects.

However, ketamine does not cause the slowed breathing and excessive sedation associated with opioid pain medicines. It also has less potential for dependence and abuse when prescribed appropriately under close medical supervision.

One of the more serious potential side effects of long-term ketamine use is cystitis (bladder inflammation). This risk seems to be dose-dependent and highest with illicit ketamine abuse at very high doses. For chronic pain patients, the risk of bladder issues is relatively low.

Is Ketamine Right for You?

If you suffer from a chronic neuropathic, cancer, severe headache, back, arthritis or fibromyalgia pain condition, ketamine therapy may provide relief when other treatments have failed. One place to find more information or a provider near you is the American Society of Ketamine Physicians, Psychotherapists & Practitioners website. There you will find a directory of clinics.

While not a magic bullet, ketamine offers new hope - especially for those who have run out of options with traditional medications. It can provide rapid improvements in pain and is one of the few drugs that addresses the central nervous system components of chronic pain.

Of course, ketamine therapy should be just one part of a comprehensive pain management plan. It does not replace other essential therapies like physical therapy, counseling, proper sleep, nutrition, exercise, and stress management.

But along with these other treatments, ketamine therapy can greatly improve quality of life for chronic pain sufferers. Speak to your doctor to see if ketamine could be appropriate for your particular situation.

About the author:

Dr. Harold Pierre is a board-certified anesthesiologist and addiction medicine specialist with over 20 years of experience. He is board-certified by the American Board of Anesthesiology and the American Board of Preventive Medicine.

This website is provided for educational and informational purposes only and does not constitute providing medical advice or professional services. The information provided should not be used for diagnosing or treating a health problem or disease, and those seeking personal medical advice should consult with a licensed physician or another qualified medical professional. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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