Ketamine Infusion for Chronic Pain: What to Know

Ketamine infusions are showing great promise as a treatment for chronic pain. Let’s take a closer look at everything you need to know.

You’ll likely have heard of Ketamine and may know it as a ‘street drug’. It’s sometimes referred to as ‘special K’ or ‘super K’ – but did you know it’s also used in medical settings? Ketamine was first used in hospitals in the 1960s for its anaesthetic and sedative effects. It was later approved by the FDA for medical use in 1970.

More recently, low doses of ketamine have been used to treat chronic pain and mental illness with initial results showing promise. In this article we’ll take a look at all you need to know about ketamine and chronic pain – let’s get started.

What is Ketamine?

This 2023 review explains that ketamine is “an anesthetic and analgesic agent”. This simply means that it works as a sedative, can relieve pain, and can affect your memory.

The drug can be given orally, topically (on the skin), via intramuscular injection, or intravenously. Intravenously means it’s given through a drip into your vein. This is the most common method used to treat chronic pain.

Ketamine Infusions for Chronic Pain: The Positives

Like any treatment, there are pros and cons to ketamine infusions for chronic pain. Let’s start with how the treatment can help and the potential benefits.

How Do Ketamine Infusions Help With Chronic Pain?

Ketamine interacts with a part of the brain and nervous system known as N-methyl-D-aspartate (NMDA) receptors. Normally, a neurotransmitter called glutamate ‘turns’ this NMDA receptor on, like a switch! That makes you feel more awake and active. When ketamine is taken, it stops glutamate from activating the receptor, so instead of feeling awake, you feel sleepy and sedated.

This 2021 survey from the Scandinavian Journal of Pain explains that the NMDA receptor: “plays an important role in the development of neuroplastic changes in chronic pain, such as wind-up and central sensitization”. Central sensitization is how your nervous ‘learns’ to keep causing pain, making it chronic. When ketamine is taken, it can block or reduce the effects of central sensitization. So basically, ketamine might be able to help chronic pain patients retrain their brains away from pain!

Ketamine also interacts with other receptors and parts of the brain which reduce inflammation and have antidepressant effects. Let’s face it, living with chronic pain is incredibly difficult so it’s understandable that many pain patients struggle with depression, anxiety, and other mental illnesses. By also tackling mental illness, ketamine may be able to improve the quality of life for those of us with chronic pain.

This 2022 article explains that ketamine stimulates opioid receptors which gives it analgesic properties, meaning it can relieve pain. In fact, one study found that 42% of patients who were previously using opioids were able to come off them completely after having ketamine infusions for between seven and 14 days. Others were able to reduce their opioid use significantly.

Interestingly, evidence suggests that the effects of the treatment can be prolonged in some cases. This means patients experience pain relief for days or weeks, not just during the treatment itself.

Initial results show promise in reducing chronic pain in some patients and helping to tackle associated mood disorders. However, the evidence is still fairly new and based on small sample sizes so more research is needed.

Who Can Have Ketamine Infusions?

It’s important to note that ketamine infusions won’t be suitable for everyone and they also may not work the same way for everybody. Doctors may use ketamine infusions for chronic pain patients whose pain is severe and where other pain treatments have failed.

Ketamine is most commonly used to treat Complex Regional Pain Syndrome (CRPS) and neuropathic pain, meaning pain that affects the nerves. Research shows that CRPS patients are the most likely to benefit from ketamine treatment.

In some cases, doctors may use ketamine infusions for other types of chronic pain such as fibromyalgia, migraines, back pain, and phantom limb pain, but research on the benefits of the treatment for these conditions is limited.

Due to the risks involved, you might not be able to have ketamine infusions if any of the following apply:

  • You have untreated high blood pressure
  • You have heart disease or problems with an abnormal heart rate
  • You’re pregnant or plan to get pregnant in the near future
  • You have respiratory issues
  • You have schizophrenia or psychosis
  • You have epilepsy
  • You are on certain medications 
  • You have a history of addiction 
  • You have liver disease 
  • You have an endocrine disorder

If you have any of these factors, you might still be able to get the treatment in some cases but the risks might be higher. Your doctor will determine whether the treatment is safe and suitable for you.

Potential Benefits

For the right patient, there are several potential benefits of ketamine infusions including:

  • Reduction in pain
  • Reduction of inflammation
  • Reduced effects of central sensitization 
  • Improved mood and symptoms of mental illness
  • A relaxed, calm feeling
  • Ability to reduce other medications with serious side effects, such as opioids
  • Reduced nausea and vomiting 
  • Prolonged relief from pain symptoms
  • Another option for patients with intractable pain where other treatments have failed

The Risks and Side Effects of Ketamine Infusions

There are some risks and side effects to ketamine infusions. These adverse effects are more likely when ketamine is given in higher doses. It’s important to weigh these risks up with the potential benefits when deciding if you want to go ahead with treatment.

I know starting any new treatment can be scary, so it’s important to take your time to make a decision. Do plenty of research and don’t be afraid to ask your doctor questions.

The Risks

At the lower doses typically used for chronic pain, ketamine infusions are generally safe and you will be monitored closely throughout your treatment.

According to the UK’s National Health Service (NHS), risks include an initial period of your pain worsening before it improves. This can be distressing and hard to manage, but if you can cope with it, the pain should ease when the treatment takes effect.

Another risk is that the treatment isn’t guaranteed to be effective, even if you meet the criteria. So, there is a chance that you might go through the infusions and find that they have little to no effect on your symptoms.

If ketamine is used too frequently, it can become less effective and there is a risk of becoming dependent on the drug. Your doctor will plan out your infusion schedule carefully to reduce these risks.

Like most medications, there is a risk that you could have an allergic reaction to ketamine, but this is a very rare occurrence. There’s also a possibility of your bladder becoming inflamed, but again this is rare.

Potential Side Effects

Not everybody will experience these side effects, and their severity may vary depending on the patient. In fact, according to the NHS, 73% of patients experience no side effects.

Possible side effects include:

  • Increased heart rate and palpitations 
  • Increased blood pressure
  • Feeling lightheaded
  • Feeling drowsy and sleepy
  • Strange or vivid dreams
  • Hallucinations
  • Double vision or other visual disturbances
  • Headaches 
  • Increased secretions (like saliva)
  • Feeling hot or flushed
  • Nausea and/or vomiting
  • Light and sound sensitivity
  • Feeling restless and agitated
  • Feeling fearful or anxious
  • Unusual body movements

If you do have side effects, they will usually only last for a short time while you’re having the infusion and possibly for a little while after. If your side effects are severe or you’re finding you’re unable to cope, the medical professional giving your infusion can lower the dose or stop the treatment.

What to Expect During Treatment

Ketamine infusions are given in hospitals on either an inpatient or outpatient basis. That means you’ll either be kept in the hospital overnight or you’ll go into hospital for a few hours during the day for the infusion and then return home. This depends on your risk factors, where you live, your symptoms, and what your doctor feels is best for you.

Usually, an anaesthetist, doctor, or nurse will be there to administer your treatment. During treatment, you will either lie on a hospital bed or sit in a comfortable hospital chair.

You will be connected to an IV, meaning a needle into your hand or arm with an attached line that the medication will be given through. You will also be attached to other monitoring devices to keep an eye on your heart rate and blood pressure. All those lines can look scary at first, especially if you aren’t used to them, but they’re all there to keep you safe and ensure your medication is given properly.

The nurse or doctor may first give you some other medications through your IV to prevent side effects and help you start to feel relaxed. Then the ketamine will be given through the IV. It will start off at a very slow, low dose and then it will be increased gradually until it reaches the level best for you. The right dose will vary depending on many factors and will be decided by your doctor. Once it’s at the right level, you’ll stay attached to the IV and the infusion will continue for between 30 minutes and an hour.

When the IV is running, you may have some side effects which we discussed earlier in this article. You will likely also feel sleepy and relaxed. The goal is that your pain will be eased and you will get some relief.

During this time you will be closely monitored and can ask for help anytime you feel it’s needed. Once the infusion is finished, you will be disconnected from the lines and taken to a recovery area. You will be monitored for a while and then either allowed to go home, or taken to a ward for further monitoring if you’re an inpatient.

If you are an outpatient, you won’t be able to drive home after your infusion so you will need someone to take you. It’s also best if you have someone with you when you get home to keep an eye on you and help you if you’re feeling any short-term side effects.

If the treatment is successful, you will likely be offered further infusions over the coming weeks. The time period will be determined by your doctor. This is to help the effects last as long as possible.

It’s important to be realistic about the outcome of the treatment. It may help reduce your pain for a short time, but isn’t a long-term fix or a magical cure. It’s best used alongside other pain management techniques and treatments. The NHS explains: “Long-lasting pain relief from Ketamine infusions alone will remain elusive. Intermittent relief during peak pain periods (flare-ups) is more realistic.”

Are Ketamine Infusions Right for You?

Choosing whether ketamine infusions are right for you is down to you and your medical team. Although there are some risks, the evidence suggests the infusions are safe overall. Research so far suggests that the treatment can be helpful for chronic pain patients who meet certain criteria.

If you have severe chronic pain and haven’t had much success with other forms of treatment, it may be worth talking to your doctor about whether ketamine infusions are an option for you.

If you feel ketamine infusions aren’t right for you, don’t panic – there are lots of other pain management options that may work for you. You aren’t alone and there is hope!


  • Culp C, Kim HK and Abdi S (2021) “Ketamine Use for Cancer and Chronic Pain Management.” Front. Pharmacol. 11:599721
  • Bloomfield, A., Chan, N., Fryml, L. et al. (2023) “Ketamine for Chronic Pain and Mental Health: Regulations, Legalities, and the Growth of Infusion Clinics.” Curr Pain Headache Rep.
  • Thomas J.P. Mangnus, Krishna D. Bharwani, Dirk L. Stronks, et al. (2021) “Ketamine therapy for chronic pain in The Netherlands: a nationwide survey.” Scandinavian Journal of Pain – Volume 22 Issue 1.
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  • Sina Marzoughi David Ripsman, & May Ong , (2023), “Therapeutic effects of 7- to 14-day subanesthetic ketamine infusions for chronic pain on standardized psychiatric measures.” Pain Management.
  • Goordeen A, Zemmedhun G, Abd-Elsayed A, et al. (2022), “Ketamine infusion and its role in chronic pain.” ASRA Pain Medicine News 2022;47.
  • NHS, (2023), “Pain Clinic Consent & Documentation Form”. St. Mary’s Hospital, Isle of Wight
  • Imperial College Healthcare, NHS, (2015), “Low-dose Ketamine for the treatment of complex pain in adults inpatients.”

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