Dr Andrew Binns
Aboriginal Health
Palliative Care
An Approach to Pain Management in Palliative Care
Common Problems with Morphine Use
Dressings for Malignant Wounds
Ketamine
Lymphoedema - Palliative Physiotherapy
Antidepressants in Palliative Care
Bowel Obstruction in Palliative Care
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An old drug with a new role
Ketamine has been around for about 30 years and used by anaesthetists as a dissociative general anaesthetic. It activates the limbic system and depresses the cerebral cortex, producing profound analgesia, slight respiratory depression, cardiovascular stimulation and amnesia. The protective reflexes are maintained. Ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist.
It is because of the unique properties of ketamine that this drug has become of interest to palliative care physicians who are always on the lookout for drugs to assist patients with severe and sometimes difficult to control pain. It has particularly been looked at in the so called 'wind up' phenomena where there is a progressive increase in dorsal horn neuronal response to rapidly repeated, identical noxious stimuli. In clinical terms it may mean that simple touch input is converted into a painful sensation called allodynia. It can also mean that a painful response to any given painful stimuli is magnified (hyperalgesia) and prolonged. The 'wind up' appears to be mediated by the NMDA receptors and can be reduced by ketamine. It is very resistant to opioids and neuropathic agents.
Reference
Marie T Fallon and John Welsh. The role of ketamine in pain
control. European Journal of Palliative Care,1996:3(4) 143-146.
Clinical implications
There is evidence that NMDA receptors are involved in the
induction and maintenance of the pain response in any pain syndrome
with allodynia, hyperalgesia and prolongation of the pain response as
well as inflammatory pain, neuropathic pain, phantom limb pain and
peripheral vascular disease pain. However it is not yet clearcut as
to the exact role of ketamine in the management of these pain
syndromes and it is certainly inappropriate to get over-optimistic as
to the benefit of this drug at this stage. Its exact role in the
palliative care setting is yet to be determined.
Side-effects
Although in palliatve care ketamine is used in subanaesthetic
doses there are still the well-known side-effects seen after
anaesthesia using this drug. They are confusion, delerium, vivid
dreams, hallucinations and feelings of detachment from the body. Some
clinicians routinely use haloperidol or a benzodiazepine to alleviate
these distressing symptoms.
Ketamine and opioids
There is evidence that ketamine reverses morphine tolerance and
clinically this results in the reappearance of morphine sensitivity.
In practical terms this means that it is necessary to reduce the
morphine dose at the same time as introducing ketamine to avoid the
problems associated with morphine toxicity. It may need to be reduced
by 30-50%.
Dosage
The doses recommended are 10-30mg stat, given subcutaneously (sc),
then starting an infusion dose of 300mg/ 24hrs via a syringe driver,
then 350mgm/24hr etc to maximum of about 700mg/24hr. Alternatively,
rather than using a syringe driver intermittent doses can be given
by the sc route.This may also have a role for painful wound
dressings.
Summary
Ketamine may have a role to play in carefully selected patients
with severe intractable pain that has not responded to conventional
analgesics used appropriately in adequate doses. However research is
still underway to clearly define where this drug fits into the drug
therapy for palliative care patients. Other related drugs with less
potential side-effects may come on to the market in the future. Until
we hear more it is appropriate to just be aware that this drug is
being trialled in the palliative care setting.
Discussion
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effects on liver Ian, icreese@aol.com Posted 12/7/2001 4:58 PM any information about toxic effects on the liver - especially on top of chronic hep B? Thanks |
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school report jessica , curlyqs136@aol.com Posted 9/12/2000 4:13 AM please send me more info. on ketamine for a 8th grade science project my group and i are having trouble find infomation we also need to know if ketamine is a plant? if so please send me a picture thxs |
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ketamine used in dogs Martha Naranjo, maray@telesat.com.co Posted 29/9/2000 2:07 PM |
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ketamine used in animals Jody, elise@telusplanet.net Posted 19/8/2000 10:48 PM I own alpacas and one of the girls is very hypersensitive to being touched. I was given advice that I should try giving her ketamine orally but now after reading about it I am not so sure. Could you please contact me if you have any advice on animal treatment. Please be advise that they have 3 stomachs and I am concerned about upsetting their digestive tract as well. Thank you. |
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Ketamine and Zyprexa Boognish, QuantumMind@Phreaker.net Posted 23/6/00 10:03 AM I would like to know if there is any danger on using Ketamine while under treatment with Zyprexa (Olanzapine), which is an atypical anti psychotic. Any info appreciated. |
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Intravenous Ketamine Leah Fensham, leahf@telstra.easymail.com.au Posted 28/5/00 9:16 PM I am requiring information regarding the intravenous treatment of ketamine for chronic back pain. My mother is going into hospital for the treatment shortly and so far little information has been available. Thanks Leah Louise Cameron, louisebcameron@hotmail.com Posted 19/6/2001 11:03 PM I work for a homecare company and have been requested to provide end stage ovarian and testicular cancer patients with continuous IV ketamine for intractable pain. In order to do this, we need stability data on the drug mixed in solution. Any suggestions? So far calls to the manufacturer have not been helpful. Do you dilute the drug to give it contiuous sc? If so, do you have any information that would be helpful to me? Thank you. |
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ORAL KETAMINE sara silva alexandre, sfcapuchos@mail.telepac.pt Posted 24/2/00 9:54 PM I¥m an hospital pharmacist. I¥m looking for urgent information on long term oral administration of ketamine for neuropathic pain, specialy on the formulation to be used. thank you. sara silva alexandre Hamish, Hamish12@hotmail.com Posted 12/2/2001 3:56 AM Dear Sara A switch to the oral route should be considered if pain control is stable and the patient can take medication orally. Starting dose 10mg four times daily. Little info on stability. Arbituary shelf life of 1 week given. |
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ketamine as a palliative for rsd/crps pain Vic Collins, vicc@micoks.net Posted 16/1/00 8:41 AM I would like to know if there is any information on the use of ketamine to reduce the surface burning sensation of rsd/crps Jackie Krizmanic, krizo@primus.com.au Posted 29/2/00 12:03 PM My Auntie has had cronic back pain for as long as I can remember she has had many operations including putting pads in to use a stimulator to control the pain. She has been advised by her doctor that they would like to try Ketamine Infusion. I would be grateful if I could get any information at all on this procedure. She is waiting for her doctor to get back to her so she will probably be going into hospital this week. Thanking you in anticipation Marta Sofia Lopez Rodriguez, marlesof@infomed.sld.cu Posted 2/8/2000 1:53 PM |
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Long term side effects Ed de Wit, edewit@oberon.ark.com Posted 23/11/99 5:19 PM To make the story short. I had surgery on my back, after the operation they Liz Wallace, lizw@eisa.net.au Posted 2/1/00 11:52 PM I had a ketamine continuous infusion in november 1999 for two weeks for chronic pain. While I had excellent results in hospital and for a further two weeks after. I now have chronic pain back. Has anyone had long term relief. As I would be happy to have this procedure done again if I got a longer period of pain relief.
regards liz bill lowry, bbl72@yahoo.com Posted 19/4/2001 7:08 AM one week ago today i took ketamine.i still feel it's effects.dizzy,but not spinning,head floating somewhat.when will these effects go away?am i damaged for life? a couple times i felt almost normal but than it comes on again. Jennifer, liljenn5@aol.com Posted 23/8/01 8:05 AM I am curious on the long term side effects on the lungs. |
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Ketamine and haloperidol to be used in palliative care mary, prin9919@aol.com Posted 5/5/99 3:43 AM Why is it so hard to find the long term affects of ketamine abuse. , diamond7900 Posted 24/6/99 2:37 AM can you please inform me of the colour lable differnce? (ie blue, yellow, red) Sarah Boon, dsboon@xtra.co.nz Posted 13/7/99 10:28 AM I was given a sub cut continuous infusion of ketamine for severe reflex sympathetic dystrophy, the infusion lasted 6 weeks, I had some amazing side effects and because I was a nurse I was left to draw up and administer this through a syringe driver. The infusion was stopped abruptly after 6 weeks, within 24 hours I began having seizures, Could this be related to the ketamines withdrawl? The doctors that were treating me said that it was a hysterical reaction to the pain that I was experiencing, I really doubt this an would love some answers if anyone could help. Thank You in Anticipation |
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Ketamine and haloperidol to be used in palliative care chinjal patel, cpat@dmu.ac.uk Posted 04/11 22:05 please could you send me more information on the compatibility of ketamine and haloperidol mixed in a syringe for use in palliative care |
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