What is ketamine?
Ketamine is best described as a “dissociative anesthetic” medicine and has been used in anesthesia and pain medicine for a number of years now. At lower sub-anaesthetic doses ketamine has been used in the treatment of conditions such as:
- Neuropathic (nerve) pain
- Fibromyalgia/complex widespread pain disorders
- Complex regional pain syndrome (CRPS)
- Phantom limb pain
- Reversing the pain associated with sensitisation of the nervous system
- Reduction of harmful opioid medication use
- Treatment resistant depression, post-traumatic stress disorder (PTSD) and addiction disorders
How does ketamine work?
Ketamine exerts its effect via a myriad of pathways. However, it is ketamine’s action on a nerve receptor called NMDA (N-methyl-D-aspartate) that seems to be most significant. Activation of the NMDA receptor plays an important role in pain, mood, cognition and neural sensitisation.
Ketamine acts to block the action of the NMDA receptor and “reset” the amplified pain receptors and repair damaged nerves. In depression ketamine creates new healthier nerve cells in the emotional centres of the brain.
Are there any side effects?
Like all drugs ketamine is not without its potential side effects. Everyone has a different tolerance to ketamine; you may not see any, only one or more of these side effects. Many of these side effects are dose dependent, meaning as the dose increases so does the risk of these occurring. Therefore, if these side effects occur it can be managed by reducing the dose/rate of the infusion or stopping the infusion temporarily. Some of these side effects can also be reduced by using other medications. If any of these side effects occur, they will usually stop once the ketamine infusion has been ceased.
Some potential side effects are:
- Euphoria or dysphoria
- Dizziness and/or light headedness
- Feeling confused or “drunk”
- Vivid dreaming
- Visual disturbances (double vision, blurry vision, hallucinations)
- Nausea and/or vomiting
- Elevated blood pressure and heart rate
- Trouble passing urine
- Jerky movements
- Allergic reactions (rare)
- Infection at site of needle: risk reduced by changing the needle site
- Blood clots (related to prolonged hospital admissions due to immobility): can be effectively prevented by keeping active such as walking around ward
Do I need to do anything before I can have a ketamine infusion?
Yes, prior to all ketamine treatments with Anodyne you will have to undergo screening for suitability. Screening is a way of ensuring that ketamine therapy is right for you and can be completed safely. Only once treatment is given the medical go ahead can treatment be booked.
Screening involves the completion of a number of questionnaires, blood (liver and kidney function), urine (bladder function) and pregnancy (if female) tests. Once completed you will have a review with one of our doctors who will complete a comprehensive medical assessment. Once completed and if approved for treatment, you will have your weight measured and a prescription for treatment set.
The screening appointment may require additional tests being completed before treatment is approved. If there are any incidental findings as part of your ketamine screening these will be discussed with you, but if there are any additional testing requirements as part of these findings we will need to discuss this with your general practitioner.
Please be aware that in some instances your Anodyne doctor may need to contact the Department of Health to discuss your previous prescribing and if relevant any substance use disorder history. This is in line with the requirements of ketamine prescribing legislation. Further details can be found at the Department of Health website.
Are there any reasons why I would not be able to have a ketamine infusion?
In general, there are a few reasons why you would not be approved for ketamine treatment.
If you do not have an indication that is likely to be assisted by ketamine then it is unlikely the treatment will be approved. If you are pregnant, have any serious cardiac, liver, psychiatric (e.g. psychosis or schizophrenia) or neurological conditions, or have had a previous allergic reaction to ketamine, then a ketamine infusion will not be suitable for you. As part of any medical treatment you will need to be able to consent to treatment otherwise it will not be able to go ahead.
These are only some of the things that your doctor will assess to determine suitability to treatment. Your individual circumstances will also be considered during screening.
How is a ketamine infusion completed?
Anodyne will usually complete a course of treatment(s) as part of an initial treatment phase. If effective, then you may be a candidate for a maintenance treatment phase. In general, pain related indications require longer and higher dose infusions. Psychiatric related indications usually follow the opposite to pain with shorter and lower dose infusions. The maintenance phase of treatment can vary according to response, with wide variability in terms of frequency of treatment. This will be discussed with you in your screening appointment with your doctor.
Where are ketamine infusions completed?
Ketamine treatment can be completed as an outpatient via The Anodyne Centre. Alternatively, there are limited hospital admission options. If for pain, there is the option to complete treatment as part of a 5-7 day admission to hospital. If psychiatric related, the initial treatment phase can be completed as part of a 2 week admission to Marian Centre Hospital. For any maintenance treatment, this will be completed as an outpatient via The Anodyne Centre.
How long does each treatment take?
The length of each ketamine treatment can vary according to the condition being treated and if you are doing it as an inpatient vs outpatient. As an outpatient, for psychiatric related indications this can be up to 2 hours and for pain this can be anywhere from 3-8 hours. These times include the treatment and post treatment observations. If you are completing ketamine infusion for pain as part of a hospital admission, then you could be connected to treatment continuously for up to 7 days.
How are ketamine infusions administered?
Anodyne conducts ketamine infusions as either an IV (intra- venous, in the vein) or SC (subcutaneously, under the skin) drip.
What happens during a ketamine infusion at Anodyne?
You will be admitted by one our nurses for a day admission and asked to toilet beforehand. The nurses will then go over some questions, measure your weight and take some observations. Observations include measures of your temperature, heart rate and rhythm, respiratory rate, blood pressure, blood oxygen saturation and pain scores. These observations are an essential part of treatment as ketamine can cause changes to these parameters. They will return to normal after you have completed the treatment.
You will then be seated in the treatment chair and connected to an observations monitor. You will then be provided with some medications. Medications can vary, but all are to help prevent some of the side effects that can happen with ketamine. Please see below for medications used.
An IV/SC needle with a catheter will then be inserted. The ketamine treatment is then connected via a tube inserted into the catheter. The treatment is carefully regulated and administered by a special automated infusion pump to ensure the correct dose and rate is given.
During the infusion you will have regular observations measured from the nursing staff. You will have the option to listen to music and use any personal portable device while the room is dimly lit for comfort. Two nurses will be present in the room at all times with you and a doctor will be in an adjacent room.
During the treatment course the first few sessions may require some dosage changes. This will be based on optimising the dose for effectiveness and to deal with any side effects if these have occurred.
Once the infusion is complete you will be disconnected from the infusion and the IV/SC catheter removed. There will be a short period of observation on the treatment chair before you are moved to the discharge area for a further period of observation. Once ready, you will be discharged to the care of your support person.
Will I need to do anything before each treatment?
You will have a nurse contact you before your first treatment to go over any specific pre-treatment requirements. These include, but are not limited to, fasting and medication requirements. If you have diabetes you will normally be having treatment first thing in the morning and you will be required to have your diabetes medication after treatment once fasting is over. You will also find general instructions on the Ketamine Treatment Guidelines documentation that is provided as part of your screening.
Will I need any other medications?
As mentioned above, as part of your ketamine infusion you may receive other medications to assist in preventing any potential and unwanted side effects. This will vary depending on your individual circumstances, but can include:
- Nausea: ondansetron, domperidone, haloperidol, and/or lorazepam
- Agitation, insomnia, feeling unsettled: lorazepam, diazepam, haloperidol, and/or clonidine
- Blood pressure and heart rate changes: clonidine, metoprolol and/or amlodipine
What happens after the infusion?
You will find general instructions on the Ketamine Treatment Guidelines documentation that is provided as part of your screening.
Once observations have returned to normal and you are safe to go home, you will be discharged to the care of your support person. Some patients may feel unsettled after stopping the infusion. If this occurs it is a normal experience and usually self resolves.
You will not be able to sign any legally binding documents, drive a motor vehicle or operate machinery for 24 hours after stopping the ketamine infusion. And we recommend you have a support person with your during this period.
How effective is ketamine?
The effectiveness of ketamine infusion therapy does vary and difficult to predict before the infusion. There are a number of factors that can contribute to this variability, with the condition being treated, the ‘optimal’ dose being achieved and individual differences being important considerations.
In general terms, pain related conditions can see an improvement during and after the treatment course has been completed, but in many patient’s the complete benefit of ketamine can sometimes take a several weeks to develop. In depression and PTSD, a positive response can be seen during and usually within 2 hours of the infusion stopping. While these are the typical benefits seen when treatment is effective, not all people have an effective response.
Reductions to pain intensity and improvement to mood are just two measures of success with ketamine therapy. Improved emotional wellbeing, functionality, sleep and quality of life, and reduction in opioid analgesia (for pain related conditions) are all additional successful measures we use to assess the effectiveness of ketamine.
How long do the benefits of ketamine last?
The duration of benefit with ketamine infusion does vary. There are a number of factors that can contribute to this variability, with the condition being treated and individual differences being important considerations. Therefore, it is difficult to predict the duration of response before the infusion.
In depression, the benefits are usually short lived and will often not last beyond a few weeks. There are a small proportion of people who we call “super responders” and reflects an extended period of benefit after a single infusion that can last several months. These are rare however and not commonly seen. In pain related conditions, the benefits can sometimes be several months. While these are the typical durations seen when treatment is effective, not all people have an effective response.
If the benefit of ketamine is short lived, what can I do to make it last longer?
If you are one of the likely people who do not have a sustained response to treatment there are various options depending on the condition you have.
For pain related conditions, one option is to have re-treatments when the effects of ketamine related benefits star to wear off. This in general can only be completed if you obtain at least 4 months of benefit. The alternative is to have a maintenance course of treatment, which can include a single infusion every so often. This is called maintenance therapy and the frequency can vary between people. An effective maintenance therapy regimen would be one that can maintain the benefits of treatment with a single infusion every month.
For depression, typically a maintenance regimen would be needed together with the addition of alternative antidepressant therapies. It is unlikely that re-treatment could be completed as the benefits of ketamine will typically be short lived. The frequency of maintenance regimen would also vary depending on your response, but a single infusion monthly that maintains the treatment benefit would be considered successful.
It is important to note that the evidence for maintenance ketamine therapy is still in its infancy and the approach taken is likely to be influenced by your specific response to treatment and maintenance. Not all people will find maintenance therapy effective in sustaining a treatment response, even if they have obtained a positive response to treatment.
How safe is ketamine in the long term? How often can I have infusions?
There is no good long-term data on the safety of repeated ketamine infusions. A lot of the evidence on ketamine therapy is short term studies (less than a few months) obtained from its use in acute pain, anaesthesia, chronic pain and treatment resistant depression. There are some longer term retrospective studies from people who have used ketamine illicitly over long periods of daily use. The problem with these studies is that we do not know what has exactly been used in these people, how much and over what time frames. Therefore, the degree to which we can generalise these results to medically administered treatments is uncertain.
We can surmise from the available evidence that repeated ketamine can increase the risk of several problems, most significant being liver and bladder dysfunction, and there is some evidence to suggest cognitive difficulties and drug tolerance. Tolerance being the same dose of treatment no longer giving the same result, or needing higher doses to achieve the same result.
We are unable to predict who, if any, will experience these problems. The current limited evidence we do have suggests that single treatments every month is generally considered safe. To further ensure this safety, as part of any ketamine therapy course with Anodyne, you will need to undergo regular screening of your bodily functions. This includes blood (liver and kidney function), urine (bladder function), cognitive function and an array of questionnaire measures.
Is a ketamine infusion right for you?
If you think a ketamine infusion may be right for you talk to your doctor about it. If you would like any further information or would like to see one of our doctor’s, please do not hesitate to contact Anodyne.